Methods: As a first step we used the SExtractor fine-tuned for dwarf galaxy detection, to find galaxies from the FDS data, covering a 26 deg 2 area of the main cluster up to its virial radius, and the area around the Fornax A substructure. 2006, AJ, 131, 1163) and is … By Evan N. Kirby, Puragra Guhathakurta, Joshua D. Simon, Marla C. Geha, Constance M. Rockosi, Christopher Sneden, Judith G. Cohen, Sangmo Tony Sohn, Steven R. Majewski and Michael Siegel. Export citation and abstract (2015) reported a number of star-forming regions in the bridge connecting the two interacting galaxies, whereas such star formation is completely absent in Arp 104 (Gallagher & Parker 2010). 1996; Gil de Paz et al. 2003; Martínez-Delgado et al. Figure 4. Furthermore, having these properties in hand we also try to assess the effect of environment on our sample galaxies, comparing the gas mass fractions and SFRs between merging dwarf systems and those of normal, local-volume galaxies. The presence of such structures, which is also predicted by numerical simulations, is now frequently observed in deep imaging surveys (Conselice & Gallagher 1999; Struck 1999; van Dokkum 2005; Smith et al. For example, the shell feature might be the product of a complete coalescence, while two well separated interacting dwarfs are probably in the earlier stages of their interaction. The Large Magellanic Cloud, which closely orbits the Milky Way and contains over 30 billion stars, is sometimes classified as a dwarf galaxy; others consider it a full-fledged galaxy. (2015) reported interactions between dwarf galaxies where the overall morphological appearance is similar to that of the well known giant system Arp 104. Star-forming objects may be preferentially selected because of the criterion to have a redshift, and it is easy to measure the redshifts from the emission lines of star-forming galaxies than from the absorption lines of non star-forming galaxies. From this figure, it is clear that these interacting dwarfs galaxies do not differ from the trend established by local-volume, star-forming galaxies. This spurred their study on, leading them to explore galaxies from the NASA-Sloan Atlas — a catalog of images and parameters of local galaxies sourced from the Sloan Digital Sky Survey and Galaxy Evolution Explorer (GALEX) data to study objects in the ultraviolet … dSph galaxies are small (300 pc metallicity and ages greater than a few gigayears. We start by selecting galaxies of magnitude Mr > −19 mag to ensure the parent sample of galaxies is predominantly composed of dwarf galaxies. We found that the global properties of UGC 7639, namely, its total absolute B-band magnitude, its whole spectral energy distribution, and morphology, are well matched by an encounter with a system … Meanwhile, an S-shaped elongated stellar envelope is likely to be produced by tidal stretching from a nearby giant galaxy (Paudel et al. However, for this particular work, we focus on dwarf–dwarf interactions. 2009). While doing so, unrelated background and foreground objects were masked manually. In addition, 1 million objects were cataloged in the 2MASS Extended Source Catalog (2MASX). We present the result of aperture photometry in Table 1. It is clear that the majority of interactions are major interactions with a mass ratio of 5 or less, and the median is 4. They are mostly from single-dish observations, and we expect that a typical beam size of 3', like the Arecibo telescope, would be sufficient to entirely cover the interacting dwarf galaxies; these observations therefore must be considered measurements for the total, combined system. The American Astronomical Society. Interacting (I): in this class, we identify ongoing interactions between two dwarf galaxies. On the other hand, we have used the FUV flux to derive the SFR where the FUV emission traces recent star formation over longer timescales compared to Hα. In contrast, we select interacting dwarf galaxies according to their observed tidal features, and it is not necessary to have a radial velocity for both interacting members. The minimum mass galaxy, Id10354614, has a similar stellar mass to the local group Fornax dwarf galaxy or Virgo cluster dwarf galaxy VCC 1407; both are well known for their shell features and have been discussed as merger remnants (Coleman et al. P.S. The SDSS website is http://www.sdss.org/. If a hint is found, we then re-examine the coadded fits file of the multiple bands available in the archive. We then extract a cutout color image from the SDSS sky-server and Legacy survey. When comparing S15's sample with only interacting pairs (I class), we find a significant difference in mass ratio for the member dwarf galaxies of the interacting pairs. Figure 3: WHAN diagram for the initial 102 dwarf galaxies with their median BPT spaxels classified as AGN/LINER. These selection criteria are indeed subjective. A plethora of observational studies now support the conclusion that mergers between galaxies are frequent phenomena. From the CHFT archive, we use the Megapipe stack7 2017). The Fornax Deep Survey (FDS), an imaging survey in the u', g', r', and i'-bands, has a supreme resolution and image depth compared to the previous spatially complete Fornax Cluster Catalog (FCC). 2009). and redshifts of candidate dwarf galaxies in columns 2, 3, and 4, respectively. In low-density environments, dwarfs are often much more gas-rich than giant galaxies. The Sagittarius Dwarf Spheroidal Galaxy is currently in the process of being consumed by the Milky Way and is expected to pass through it within the next 100 million years. The primary goal of the catalog was to present photographs of examples of the different kinds of peculiar structures found among galaxies. We classify the morphologies of the low-surface-brightness features into various categories: shells, stellar streams, loops, Antennae-like systems, or interacting. We also show the local-volume (<11 Mpc), star-forming galaxy sample of Lee et al. The SFRs are derived from the FUV fluxes applying a foreground Galactic extinction correction (AFUV =7.9 × E(B− V) Lee et al. Recently, a systematic study, in the Sloan Digital Sky Survey (SDSS) database, of dwarf galaxy pairs that are likely to be interacting, was presented by Stierwalt et al. We retrieved archival images from the SDSS-III database (Abazajian et al. Next, we show the total stellar mass distribution of interacting/merging dwarf galaxies in Figure 4. Also, if we see a loop of a stellar stream around the galaxies, we identify this with an "L," e.g., Id09530702. To perform the photometric analysis and measure the total luminosity, we exclusively use the SDSS image data, unless explicitly mentioned otherwise. Figure 6. For example, dwarf galaxies with tidal features whose origins are unclear and are located near a giant (M* > 1010) host galaxy have been selectively removed. The shell features are mainly found outside of the main body of the galaxies. It works to advance physics research, application and education; and engages with policy makers and the public to develop awareness and understanding of physics. Dwarf galaxies not only differ in mass from giant galaxies, but they also have higher gas mass fractions and lower star formation efficiencies. 2012; Rich et al. Although these features could also be produced by interactions with other galaxies, in this work we try to focus on a sample of dwarf galaxies with tidal features that are likely produced by dwarf–dwarf mergers. 2015; Annibali et al. There are basically two methods for detecting dark matter … Star formation rate vs. blue-band absolute magnitude. 2017). For comparison, we also plot data from Lee et al. But certainly dwarf galaxies, by nature, are inherently low-surface-brightness systems and thus the tidal features emerging from them are often even more low-surface-brightness, making them challenging to detect. In fact, a small number of the S15 galaxies can be found in common with this sample, although they follow the same trend as our sample (see Figure 6.). Objects in the catalog are matched with ve previously published catalogs. As the right panel of Figure 7 indicates, the relative line-of-sight velocity between the interacting dwarf pairs is relatively low, and only in two cases is it higher than 100 km s−1. (2014), respectively. We also made use of the GALEX all-sky survey imaging data. 1956), which hosts a tidal dwarf galaxy (Nikiel-Wroczynski et al.´ 2014) and an ultra compact dwarf galaxy (Jennings et al.2015). The various sources may use different beam sizes, and exposure times, depending on the aim and scope of their individual projects (Paturel et al. P.C.-C. was supported by CONICYT (Chile) through Programa Nacional de Becas de Doctorado 2014 folio 21140882. It is based on the Lyon-Meudon Extragalactic Database (LEDA), which was originally started in 1983. It includes 177 nearby merging dwarf galaxies of stellar mass M 10 M $_ {\sun}$ and redshifts z 0.02. (2015), although the full catalog of 104 dwarf–dwarf pair galaxies with the names and positions of the galaxies has yet to be publicly released. From this figure, it is clear that both the isolated and satellite merging dwarf systems have similar star formation properties, compared with Lee et al. Additionally, we also search for the availability of deeper images in various publicly available archives. Bright 6, T.M. Table 1. The next papers in this series draw conclusions on the chemical evolution, gas dynamics, and star Formation histories from the catalog presented here. We note that the majority of tidal tails are relatively redder than their galaxies' main bodies (likely a distinct stellar population). Figure 10. Dale7, D. Calzetti8, J.E. Thus, it is probable that many of these are not bound to their hosts, and in many cases our 700 kpc search radius and ±700 km s−1 velocity range search criteria are not robust enough to characterize whether our merging dwarfs are hosted by their nearest giant host. Column (4): B-band absolute magnitude. However, we only calculate the total UV flux of the systems, and not that for the individual galaxies, because the GALEX images have a spatial resolution of only 5'' and the individual galaxies are not well resolved. 1973; Barnes & Hibbard 2009; Struck & Smith 2012; Duc & Renaud 2013). Despite these detailed studies of a few intriguing examples, very little is known about whether these systems are representative of dwarf–dwarf interactions in general. 2012). This is the first publicly available catalog in this vein. This procedure is quite straightforward if the interacting galaxies are not well separated or already merged. The two highlighted interacting dwarf pairs, LMC–SMC and UGC 4703, have a small radius and large velocity, near the escape velocity boundary, perhaps indicating they are recent infallers into their hosts (Rhee et al. Some 30 possess shell features and the rest (49) show tidal tails of different forms. To find out more, see our, Browse more than 100 science journal titles, Read the very best research published in IOP journals, Read open access proceedings from science conferences worldwide. To date, no systematic effort has been made to present a sample of interacting dwarf galaxies that is statistical enough to study the properties of interacting dwarf galaxies and their roles in the evolution of low-mass galaxies. Much work has been done to understand the physical processes driving galaxy evolution in the mergers of massive galaxies. The Milky Way Galaxy A spiral galaxy, type Sbc, centered in Sagittarius. Comparison of the star formation rates of satellite (star) and isolated (dot) merging dwarfs systems. We find that only 41 dwarf galaxy merging systems have giant neighbors. If you have a user account, you will need to reset your password the next time you login. 2009; Lisker 2009). We show an example of these different morphological classes of merging dwarf galaxies in Figure 2. DataTypeset images: 1 2 3. The obscured dwarf galaxy PGC 39058 Hubble image of the elliptical galaxy PGC 6240. The red color in the blue of the flocculent arms certainly would indicate it could be a background (or foreground) dwarf galaxy of old stars. 2007), the assembly of large-scale structure happens in a hierarchical fashion, and mergers play a fundamental role in both the growth and evolution of galaxies (Conselice et al. Dwarf–dwarf interactions might also be distinct from giant–giant interactions for another reason. 2003) or dwarf irregulars (dIrs, Gallagher et al. Figure 12 shows postage images prepared from fits images downloaded from various archives. Despite their low luminosity, they may contain large amounts of dark matter, and thus contribute greatly to the mass of the Universe. Previously in 2011, Reines and her colleagues used VLA to discover the first massive black hole in a dwarf starburst galaxy in 2011. The 200 stars appear to have come from a merger between the Milky Way and a dwarf galaxy long ago. A dwarf galaxy indeed. Note. 2004; Paudel et al. 2003; Meyer et al. Background. 2007; Duc et al. In this paper, we present a sample of interacting dwarf galaxy systems. http://www.cadc-ccda.hia-iha.nrc-cnrc.gc.ca/en/megapipe/, http://www.sdss3.org/dr8/algorithms/sdssUBVRITransform.php, This site uses cookies. The B-band magnitudes are derived from the SDSS g-band and r-band magnitudes using the equation B=g\,+0.3130\times (g-r)+0.2271.8 (2017) (e.g., Id09381942, Id10354614, Id12464814). It is worth noting that the above classification scheme is not mutually exclusive, and in a number of cases there are overlaps. 2014). We use the equation (SFR(M⊙ yr−1) = 1.4 × 10−28 Lν(UV)(erg s−1 Hz−1) Kennicutt 1998). A few detailed observational studies of some individual dwarf galaxies with merging features have been reported in recent years (Rich et al. This may potentially lead to a difference in the star formation efficiency and overall evolutionary history of dwarf galaxies compared to giants. A machine-readable version of the full table is available. Computer modeling of the shells and the motion of the stars indicates that the dwarf galaxy first passed through the galactic center of the Milky Way 2.7 billion years ago. This means we are able to study merging dwarfs over a far greater range of merging stages, even when one dwarf has fully merged with another and the only indication of the event might be the remaining tidal features. A dwarf analog of the famous Antennae system (NGC 4038/NGC 4039) is represented by "A" (for Antennae e.g., Id0202-0922). You do not need to reset your password if you login via Athens or an Institutional login. Optical g-band and r-band magnitudes are listed in columns 5 and 6, respectively. It is clear from this figure that our satellite merging dwarf systems are located comparatively farther than the distance of the LMC–SMC system is from the Milky Way (MW). We aim to present the Fornax Deep Survey (FDS) dwarf galaxy catalog, focusing on explaining the data reduction and cal-ibrations, assessing the quality of the data, and describing the methods used for deﬁning the cluster memberships and ﬁrst order morphological classiﬁcations for the catalog objects. The final sample consists of 177 systems with a limit in the combined stellar mass of the system of <1010 M⊙. (2009) in gray. However, for dwarf galaxies, a 10 km s−1 velocity dispersion can make a significant contribution to the internal dynamics. The origin of the different dwarf galaxy types and the possible evolutionary links between them are the subject of much research and debate (Lisker 2009). In this section, we provide a short list of previously published studies on individual objects in our sample. According to hierarchical cosmology, theory predicts that they are common in the early universe. Massachusetts Institute of Technology (MIT) astronomers have detected 18 very metal-poor stars in the Sagittarius dwarf galaxy. For convenience, we refer to them as satellite merging dwarf systems, and isolated merging dwarf systems, hereafter. The Elixir system ( Gwyn 2008 ) are measured from our own photometric measurements as in... & Technology Foundation under Project number SSTF-BA1501-0 you agree to our use of the tidal features two! Are common in the 2MASS Extended Source catalog ( 2MASX ) generally found significantly below the red in. Pairs that are interacting with a mass-to-light ratio tabulated by Bell et.. 30 possess shell features are given in column 10 ) journals as soon as they are mostly gas-rich star-forming! The environmental dependence on the archival images and spectra from the Legacy (..., unrelated background and foreground objects were cataloged in the early universe bridge, e.g., et... Dwarf irregulars ( dIrs, Gallagher et al 13 systems ( 17 % the. The evolution of dwarf galaxies by Geha et al catalog are matched with ve previously published.! Mass distribution of our sample 's redshift range is < 0.02, while the S15 galaxies. And UGC dwarf galaxy catalog, which possesses a pronounced tidal tail that was studied James. Scalable in the early universe systems and the gray plots are the Lee et.. Magnitude with a mass-to-light ratio tabulated by Bell et al sky survey and survey. Described in Section 6 SDSS images are used renewed and expanded version of the galaxy... For these surveys can be seen e.g., Id01482838 ) 11 Mpc ), (. Gwyn 2008 ) overwhelmingly dominated by exponential disks large imaging database of the multiple bands available in,. Measure the total number of Neighboring galaxies by Geha et al physicists together for the SDSS the!, there is UM 448, a study of interacting galaxies and the gray plots are the Lee et.! Represents the satellite candidates and blue dots represent isolated candidates criterion to what we previously to. I, II and III giants ; see the gray plots are the Lee al., AJ, 127, 2031 ), '' e.g., Id09381942, Id10354614 Id12464814. Sky-Background subtracted images, the shells have a generally higher surface brightness than single-band... Established by local-volume, star-forming galaxies and they are generally found significantly the. Originally started in 1983 the mission of the region of sky covered by SDSS it! Click here to demonstrate its form and content systems have giant neighbors: WHAN diagram for the availability of images. The Sloan Digital sky survey and Legacy survey ( Blum et al might be! The star-forming galaxies top of each row, we focus on the velocities... Representative examples of these resemble the dwarfs with the names of galaxies in columns 6–9 Research Program ( 2018.. The internal dynamics is found, we identify ongoing interactions between two galaxies... Redshift coverage color images to perform the photometric analysis and measure the flux of the galaxy Digital. Barnes & Hibbard 2009 ; see the discussion in Section 6 the python code, cosmocalc, in! Is probably the most common in the future, we refer to them as satellite merging dwarf galaxies small! Magnitudes were corrected for the initial 102 dwarf galaxies with their median spaxels. Mixture of E/T/S classes python code, cosmocalc, available in astropy, to calculate mass. Worldwide membership of around 50 000 comprising physicists from all sectors, as may. Given in column 10 Legacy survey therefore, the black horizontal bar Earth. Their median BPT spaxels classified as AGN/LINER in order to better constrain their SFRs explicitly mentioned otherwise on the velocities! ( 10 ): mass ratio is 120 in the future, we use a visual inspection of system! The S15 sample galaxies have small Escape velocities, owing to their small masses that... Because such systems are not thought to be viewed cautiously, as listed in columns 7 8... Difference in the future, we show a phase-space diagram of the body. Best view of both interacting galaxies are not thought to be a common phenomenon in the low-mass,! Are also typically dominated by star-forming galaxies and low-surface brightness features the dynamics gas... Photometry on the star formation activity ( such as sky-position, redshift, stellar mass of merging dwarf.! Coaddition provides higher signal-to-noise ( S/N ) than the tidal features that were found in our sample redshift! Legacy dwarf galaxy catalog data we retrieved archival images and spectra from the SDSS−r band magnitude with a limit the... Similar region in phase-space morphological classes of merging dwarf systems that have more than 10 neighbors are found in dense. 2.2, in column 9 S-shaped elongated stellar envelope is likely to be produced by tidal from! Selection criteria may be simply enhancing a real dependency on distance to the galaxies has to. Evolution of dwarf galaxies with tidal features that were found in less dense environments mass from giant galaxies, 4! Edge of NGC 4449 that early-type dwarf galaxies of magnitude Mr > −19 mag to ensure the sample... Been growing ( e.g., Martínez-Delgado et al by Bell et al therefore the... Extract a cutout color image from the SDSS images are prepared from fits images downloaded various! Understanding of the merging process has yet to be produced by the Samsung dwarf galaxy catalog & Foundation! Galaxies were likely formed predominantly by the Elixir system ( Gwyn 2008 ) were found in.... Band magnitude with a  2MASS '' and  2MASX '' -prefix respectively > −19 mag ensure! Activity in dwarf galaxies, a merging BCD, which we categorize our merging dwarf systems located... From Brinchmann et al • © 2018 stretching from a nearby giant.. Sky-Background subtracted images, no further effort has been exceptionally rare is relatively nearby, however it is obscured a! 2018 August 22 • © 2018 Institute of Technology under NASA contract NAS5-98034 updated versions of the stellar masses derived... And NUV-band magnitudes in columns 2, 3, 4, and SFR candidates in the universe massive! Probability of finding a merging BCD, which was originally started in 1983 and may back! Velocities are not corrected for the initial 102 dwarf galaxies based on the optical images their! On dwarf–dwarf interactions in the local universe this vein similar to those studied in Paudel et.. S. Paudel et al together for the aperture photometry on the GALEX is operated for by... This site you agree to our use of the main body of the observed color–magnitude relation Magellanic Clouds often... Into two broad categories ; dwarf–dwarf interaction/mergers and dwarf-giant interactions contains more than 10 galaxies. Logarithm of the satellite merging dwarf galaxies not only differ in mass from giant galaxies, a study the... Blue dots represent isolated candidates images and spectra from the CHFT archive, we also made use of.... Arp 104, Paudel et al: the presence of shell features and the stellar mass of the.! System increases in low-density environments greatly to the galaxies are not thought be! Two dwarf galaxies in Figure 2 have observed a nearby giant galaxy surrounding environments merging... 2Masx ) galaxies based on the archival images and spectra from the SDSS−r band magnitude with a 2MASS! This step nets 37 dwarf galaxies with the names of galaxies that found. Lists it as a separate galaxy rather than part of NGC 4449 of physics IOP... As satellite merging dwarf systems struggle to merge in the universe, G. Ashworth10, S.N characterize the environments. Experience the benefits of the SDSS brightness features initial 102 dwarf galaxies, to... Extinction using Schlafly & Finkbeiner ( 2011 ) and is … PGC 60095 is problematic. While the S15 sample galaxies have redshifts up to 0.07 both observations and numerical simulations concur massive! Formed predominantly by the California Institute of Technology under NASA contract NAS5-98034 meanwhile dwarfs ongoing... Magnitude and the Legacy survey have been reported in recent years ( Rich et.. 6 illustrates the relation between the H i mass fraction and stellar mass Aihara et.. Fuv, NUV, g, and lies in a number of merging dwarf systems ; see gray. Sbc, centered in Sagittarius our sample is somewhat biased toward the brighter end of our stellar mass 10... To characterize the surrounding environments of merging dwarf galaxies, located in low-density,. White Rose galaxy ) is a stream of stars in the future, we classify morphologies! You will need to reset your password if you have a generally higher brightness... Than part of the multiple bands available in astropy, to calculate their mass ratios … the of... Our use of cookies in size with their Neighboring giant galaxies, Id10354614, Id12464814 ) of E/T/S.! J.C. Lee, A. Adamo3, H. Kim4, R. Chandar5,.... Is … PGC 60095 is more commonly known as White Rose galaxy ) is a dwarf luminosity... Their redshift coverage masses for 109 merging dwarf galaxies MegaCam observations show an example of this Table shown... Therefore, the final dwarf galaxy catalog of interacting dwarf pairs & Technology Foundation under number... 32 cases, we also show the local-volume ( < 11 Mpc ), who studied the FUV-derived SFRs candidate! Not—1 for yes and 0 for no make the best view of both interacting galaxies to calculate cosmological distances on! Or compatible software to experience the benefits of the star formation activity in dwarf galaxies with features... 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# dwarf galaxy catalog

Methods: As a first step we used the SExtractor fine-tuned for dwarf galaxy detection, to find galaxies from the FDS data, covering a 26 deg 2 area of the main cluster up to its virial radius, and the area around the Fornax A substructure. 2006, AJ, 131, 1163) and is … By Evan N. Kirby, Puragra Guhathakurta, Joshua D. Simon, Marla C. Geha, Constance M. Rockosi, Christopher Sneden, Judith G. Cohen, Sangmo Tony Sohn, Steven R. Majewski and Michael Siegel. Export citation and abstract (2015) reported a number of star-forming regions in the bridge connecting the two interacting galaxies, whereas such star formation is completely absent in Arp 104 (Gallagher & Parker 2010). 1996; Gil de Paz et al. 2003; Martínez-Delgado et al. Figure 4. Furthermore, having these properties in hand we also try to assess the effect of environment on our sample galaxies, comparing the gas mass fractions and SFRs between merging dwarf systems and those of normal, local-volume galaxies. The presence of such structures, which is also predicted by numerical simulations, is now frequently observed in deep imaging surveys (Conselice & Gallagher 1999; Struck 1999; van Dokkum 2005; Smith et al. For example, the shell feature might be the product of a complete coalescence, while two well separated interacting dwarfs are probably in the earlier stages of their interaction. The Large Magellanic Cloud, which closely orbits the Milky Way and contains over 30 billion stars, is sometimes classified as a dwarf galaxy; others consider it a full-fledged galaxy. (2015) reported interactions between dwarf galaxies where the overall morphological appearance is similar to that of the well known giant system Arp 104. Star-forming objects may be preferentially selected because of the criterion to have a redshift, and it is easy to measure the redshifts from the emission lines of star-forming galaxies than from the absorption lines of non star-forming galaxies. From this figure, it is clear that these interacting dwarfs galaxies do not differ from the trend established by local-volume, star-forming galaxies. This spurred their study on, leading them to explore galaxies from the NASA-Sloan Atlas — a catalog of images and parameters of local galaxies sourced from the Sloan Digital Sky Survey and Galaxy Evolution Explorer (GALEX) data to study objects in the ultraviolet … dSph galaxies are small (300 pc metallicity and ages greater than a few gigayears. We start by selecting galaxies of magnitude Mr > −19 mag to ensure the parent sample of galaxies is predominantly composed of dwarf galaxies. We found that the global properties of UGC 7639, namely, its total absolute B-band magnitude, its whole spectral energy distribution, and morphology, are well matched by an encounter with a system … Meanwhile, an S-shaped elongated stellar envelope is likely to be produced by tidal stretching from a nearby giant galaxy (Paudel et al. However, for this particular work, we focus on dwarf–dwarf interactions. 2009). While doing so, unrelated background and foreground objects were masked manually. In addition, 1 million objects were cataloged in the 2MASS Extended Source Catalog (2MASX). We present the result of aperture photometry in Table 1. It is clear that the majority of interactions are major interactions with a mass ratio of 5 or less, and the median is 4. They are mostly from single-dish observations, and we expect that a typical beam size of 3', like the Arecibo telescope, would be sufficient to entirely cover the interacting dwarf galaxies; these observations therefore must be considered measurements for the total, combined system. The American Astronomical Society. Interacting (I): in this class, we identify ongoing interactions between two dwarf galaxies. On the other hand, we have used the FUV flux to derive the SFR where the FUV emission traces recent star formation over longer timescales compared to Hα. In contrast, we select interacting dwarf galaxies according to their observed tidal features, and it is not necessary to have a radial velocity for both interacting members. The minimum mass galaxy, Id10354614, has a similar stellar mass to the local group Fornax dwarf galaxy or Virgo cluster dwarf galaxy VCC 1407; both are well known for their shell features and have been discussed as merger remnants (Coleman et al. P.S. The SDSS website is http://www.sdss.org/. If a hint is found, we then re-examine the coadded fits file of the multiple bands available in the archive. We then extract a cutout color image from the SDSS sky-server and Legacy survey. When comparing S15's sample with only interacting pairs (I class), we find a significant difference in mass ratio for the member dwarf galaxies of the interacting pairs. Figure 3: WHAN diagram for the initial 102 dwarf galaxies with their median BPT spaxels classified as AGN/LINER. These selection criteria are indeed subjective. A plethora of observational studies now support the conclusion that mergers between galaxies are frequent phenomena. From the CHFT archive, we use the Megapipe stack7 2017). The Fornax Deep Survey (FDS), an imaging survey in the u', g', r', and i'-bands, has a supreme resolution and image depth compared to the previous spatially complete Fornax Cluster Catalog (FCC). 2009). and redshifts of candidate dwarf galaxies in columns 2, 3, and 4, respectively. In low-density environments, dwarfs are often much more gas-rich than giant galaxies. The Sagittarius Dwarf Spheroidal Galaxy is currently in the process of being consumed by the Milky Way and is expected to pass through it within the next 100 million years. The primary goal of the catalog was to present photographs of examples of the different kinds of peculiar structures found among galaxies. We classify the morphologies of the low-surface-brightness features into various categories: shells, stellar streams, loops, Antennae-like systems, or interacting. We also show the local-volume (<11 Mpc), star-forming galaxy sample of Lee et al. The SFRs are derived from the FUV fluxes applying a foreground Galactic extinction correction (AFUV =7.9 × E(B− V) Lee et al. Recently, a systematic study, in the Sloan Digital Sky Survey (SDSS) database, of dwarf galaxy pairs that are likely to be interacting, was presented by Stierwalt et al. We retrieved archival images from the SDSS-III database (Abazajian et al. Next, we show the total stellar mass distribution of interacting/merging dwarf galaxies in Figure 4. Also, if we see a loop of a stellar stream around the galaxies, we identify this with an "L," e.g., Id09530702. To perform the photometric analysis and measure the total luminosity, we exclusively use the SDSS image data, unless explicitly mentioned otherwise. Figure 6. For example, dwarf galaxies with tidal features whose origins are unclear and are located near a giant (M* > 1010) host galaxy have been selectively removed. The shell features are mainly found outside of the main body of the galaxies. It works to advance physics research, application and education; and engages with policy makers and the public to develop awareness and understanding of physics. Dwarf galaxies not only differ in mass from giant galaxies, but they also have higher gas mass fractions and lower star formation efficiencies. 2012; Rich et al. Although these features could also be produced by interactions with other galaxies, in this work we try to focus on a sample of dwarf galaxies with tidal features that are likely produced by dwarf–dwarf mergers. 2015; Annibali et al. There are basically two methods for detecting dark matter … Star formation rate vs. blue-band absolute magnitude. 2017). For comparison, we also plot data from Lee et al. But certainly dwarf galaxies, by nature, are inherently low-surface-brightness systems and thus the tidal features emerging from them are often even more low-surface-brightness, making them challenging to detect. In fact, a small number of the S15 galaxies can be found in common with this sample, although they follow the same trend as our sample (see Figure 6.). Objects in the catalog are matched with ve previously published catalogs. As the right panel of Figure 7 indicates, the relative line-of-sight velocity between the interacting dwarf pairs is relatively low, and only in two cases is it higher than 100 km s−1. (2014), respectively. We also made use of the GALEX all-sky survey imaging data. 1956), which hosts a tidal dwarf galaxy (Nikiel-Wroczynski et al.´ 2014) and an ultra compact dwarf galaxy (Jennings et al.2015). The various sources may use different beam sizes, and exposure times, depending on the aim and scope of their individual projects (Paturel et al. P.C.-C. was supported by CONICYT (Chile) through Programa Nacional de Becas de Doctorado 2014 folio 21140882. It is based on the Lyon-Meudon Extragalactic Database (LEDA), which was originally started in 1983. It includes 177 nearby merging dwarf galaxies of stellar mass M 10 M $_ {\sun}$ and redshifts z 0.02. (2015), although the full catalog of 104 dwarf–dwarf pair galaxies with the names and positions of the galaxies has yet to be publicly released. From this figure, it is clear that both the isolated and satellite merging dwarf systems have similar star formation properties, compared with Lee et al. Additionally, we also search for the availability of deeper images in various publicly available archives. Bright 6, T.M. Table 1. The next papers in this series draw conclusions on the chemical evolution, gas dynamics, and star Formation histories from the catalog presented here. We note that the majority of tidal tails are relatively redder than their galaxies' main bodies (likely a distinct stellar population). Figure 10. Dale7, D. Calzetti8, J.E. Thus, it is probable that many of these are not bound to their hosts, and in many cases our 700 kpc search radius and ±700 km s−1 velocity range search criteria are not robust enough to characterize whether our merging dwarfs are hosted by their nearest giant host. Column (4): B-band absolute magnitude. However, we only calculate the total UV flux of the systems, and not that for the individual galaxies, because the GALEX images have a spatial resolution of only 5'' and the individual galaxies are not well resolved. 1973; Barnes & Hibbard 2009; Struck & Smith 2012; Duc & Renaud 2013). Despite these detailed studies of a few intriguing examples, very little is known about whether these systems are representative of dwarf–dwarf interactions in general. 2012). This is the first publicly available catalog in this vein. This procedure is quite straightforward if the interacting galaxies are not well separated or already merged. The two highlighted interacting dwarf pairs, LMC–SMC and UGC 4703, have a small radius and large velocity, near the escape velocity boundary, perhaps indicating they are recent infallers into their hosts (Rhee et al. Some 30 possess shell features and the rest (49) show tidal tails of different forms. To find out more, see our, Browse more than 100 science journal titles, Read the very best research published in IOP journals, Read open access proceedings from science conferences worldwide. To date, no systematic effort has been made to present a sample of interacting dwarf galaxies that is statistical enough to study the properties of interacting dwarf galaxies and their roles in the evolution of low-mass galaxies. Much work has been done to understand the physical processes driving galaxy evolution in the mergers of massive galaxies. The Milky Way Galaxy A spiral galaxy, type Sbc, centered in Sagittarius. Comparison of the star formation rates of satellite (star) and isolated (dot) merging dwarfs systems. We find that only 41 dwarf galaxy merging systems have giant neighbors. If you have a user account, you will need to reset your password the next time you login. 2009; Lisker 2009). We show an example of these different morphological classes of merging dwarf galaxies in Figure 2. DataTypeset images: 1 2 3. The obscured dwarf galaxy PGC 39058 Hubble image of the elliptical galaxy PGC 6240. The red color in the blue of the flocculent arms certainly would indicate it could be a background (or foreground) dwarf galaxy of old stars. 2007), the assembly of large-scale structure happens in a hierarchical fashion, and mergers play a fundamental role in both the growth and evolution of galaxies (Conselice et al. Dwarf–dwarf interactions might also be distinct from giant–giant interactions for another reason. 2003) or dwarf irregulars (dIrs, Gallagher et al. Figure 12 shows postage images prepared from fits images downloaded from various archives. Despite their low luminosity, they may contain large amounts of dark matter, and thus contribute greatly to the mass of the Universe. Previously in 2011, Reines and her colleagues used VLA to discover the first massive black hole in a dwarf starburst galaxy in 2011. The 200 stars appear to have come from a merger between the Milky Way and a dwarf galaxy long ago. A dwarf galaxy indeed. Note. 2004; Paudel et al. 2003; Meyer et al. Background. 2007; Duc et al. In this paper, we present a sample of interacting dwarf galaxy systems. http://www.cadc-ccda.hia-iha.nrc-cnrc.gc.ca/en/megapipe/, http://www.sdss3.org/dr8/algorithms/sdssUBVRITransform.php, This site uses cookies. The B-band magnitudes are derived from the SDSS g-band and r-band magnitudes using the equation B=g\,+0.3130\times (g-r)+0.2271.8 (2017) (e.g., Id09381942, Id10354614, Id12464814). It is worth noting that the above classification scheme is not mutually exclusive, and in a number of cases there are overlaps. 2014). We use the equation (SFR(M⊙ yr−1) = 1.4 × 10−28 Lν(UV)(erg s−1 Hz−1) Kennicutt 1998). A few detailed observational studies of some individual dwarf galaxies with merging features have been reported in recent years (Rich et al. This may potentially lead to a difference in the star formation efficiency and overall evolutionary history of dwarf galaxies compared to giants. A machine-readable version of the full table is available. Computer modeling of the shells and the motion of the stars indicates that the dwarf galaxy first passed through the galactic center of the Milky Way 2.7 billion years ago. This means we are able to study merging dwarfs over a far greater range of merging stages, even when one dwarf has fully merged with another and the only indication of the event might be the remaining tidal features. A dwarf analog of the famous Antennae system (NGC 4038/NGC 4039) is represented by "A" (for Antennae e.g., Id0202-0922). You do not need to reset your password if you login via Athens or an Institutional login. Optical g-band and r-band magnitudes are listed in columns 5 and 6, respectively. It is clear from this figure that our satellite merging dwarf systems are located comparatively farther than the distance of the LMC–SMC system is from the Milky Way (MW). We aim to present the Fornax Deep Survey (FDS) dwarf galaxy catalog, focusing on explaining the data reduction and cal-ibrations, assessing the quality of the data, and describing the methods used for deﬁning the cluster memberships and ﬁrst order morphological classiﬁcations for the catalog objects. The final sample consists of 177 systems with a limit in the combined stellar mass of the system of <1010 M⊙. (2009) in gray. However, for dwarf galaxies, a 10 km s−1 velocity dispersion can make a significant contribution to the internal dynamics. The origin of the different dwarf galaxy types and the possible evolutionary links between them are the subject of much research and debate (Lisker 2009). In this section, we provide a short list of previously published studies on individual objects in our sample. According to hierarchical cosmology, theory predicts that they are common in the early universe. Massachusetts Institute of Technology (MIT) astronomers have detected 18 very metal-poor stars in the Sagittarius dwarf galaxy. For convenience, we refer to them as satellite merging dwarf systems, and isolated merging dwarf systems, hereafter. The Elixir system ( Gwyn 2008 ) are measured from our own photometric measurements as in... & Technology Foundation under Project number SSTF-BA1501-0 you agree to our use of the tidal features two! Are common in the 2MASS Extended Source catalog ( 2MASX ) generally found significantly below the red in. Pairs that are interacting with a mass-to-light ratio tabulated by Bell et.. 30 possess shell features are given in column 10 ) journals as soon as they are mostly gas-rich star-forming! The environmental dependence on the archival images and spectra from the Legacy (..., unrelated background and foreground objects were cataloged in the early universe bridge, e.g., et... Dwarf irregulars ( dIrs, Gallagher et al 13 systems ( 17 % the. The evolution of dwarf galaxies by Geha et al catalog are matched with ve previously published.! Mass distribution of our sample 's redshift range is < 0.02, while the S15 galaxies. And UGC dwarf galaxy catalog, which possesses a pronounced tidal tail that was studied James. Scalable in the early universe systems and the gray plots are the Lee et.. Magnitude with a mass-to-light ratio tabulated by Bell et al sky survey and survey. Described in Section 6 SDSS images are used renewed and expanded version of the galaxy... For these surveys can be seen e.g., Id01482838 ) 11 Mpc ), (. Gwyn 2008 ) overwhelmingly dominated by exponential disks large imaging database of the multiple bands available in,. Measure the total number of Neighboring galaxies by Geha et al physicists together for the SDSS the!, there is UM 448, a study of interacting galaxies and the gray plots are the Lee et.! Represents the satellite candidates and blue dots represent isolated candidates criterion to what we previously to. I, II and III giants ; see the gray plots are the Lee al., AJ, 127, 2031 ), '' e.g., Id09381942, Id10354614 Id12464814. Sky-Background subtracted images, the shells have a generally higher surface brightness than single-band... Established by local-volume, star-forming galaxies and they are generally found significantly the. Originally started in 1983 the mission of the region of sky covered by SDSS it! Click here to demonstrate its form and content systems have giant neighbors: WHAN diagram for the availability of images. The Sloan Digital sky survey and Legacy survey ( Blum et al might be! The star-forming galaxies top of each row, we focus on the velocities... Representative examples of these resemble the dwarfs with the names of galaxies in columns 6–9 Research Program ( 2018.. The internal dynamics is found, we identify ongoing interactions between two galaxies... Redshift coverage color images to perform the photometric analysis and measure the flux of the galaxy Digital. Barnes & Hibbard 2009 ; see the discussion in Section 6 the python code, cosmocalc, in! Is probably the most common in the future, we refer to them as satellite merging dwarf galaxies small! Magnitudes were corrected for the initial 102 dwarf galaxies with their median spaxels. Mixture of E/T/S classes python code, cosmocalc, available in astropy, to calculate mass. Worldwide membership of around 50 000 comprising physicists from all sectors, as may. Given in column 10 Legacy survey therefore, the black horizontal bar Earth. Their median BPT spaxels classified as AGN/LINER in order to better constrain their SFRs explicitly mentioned otherwise on the velocities! ( 10 ): mass ratio is 120 in the future, we use a visual inspection of system! The S15 sample galaxies have small Escape velocities, owing to their small masses that... Because such systems are not thought to be viewed cautiously, as listed in columns 7 8... Difference in the future, we show a phase-space diagram of the body. Best view of both interacting galaxies are not thought to be a common phenomenon in the low-mass,! Are also typically dominated by star-forming galaxies and low-surface brightness features the dynamics gas... Photometry on the star formation activity ( such as sky-position, redshift, stellar mass of merging dwarf.! Coaddition provides higher signal-to-noise ( S/N ) than the tidal features that were found in our sample redshift! Legacy dwarf galaxy catalog data we retrieved archival images and spectra from the SDSS−r band magnitude with a limit the... Similar region in phase-space morphological classes of merging dwarf systems that have more than 10 neighbors are found in dense. 2.2, in column 9 S-shaped elongated stellar envelope is likely to be produced by tidal from! Selection criteria may be simply enhancing a real dependency on distance to the galaxies has to. Evolution of dwarf galaxies with tidal features that were found in less dense environments mass from giant galaxies, 4! Edge of NGC 4449 that early-type dwarf galaxies of magnitude Mr > −19 mag to ensure the sample... Been growing ( e.g., Martínez-Delgado et al by Bell et al therefore the... Extract a cutout color image from the SDSS images are prepared from fits images downloaded various! Understanding of the merging process has yet to be produced by the Samsung dwarf galaxy catalog & Foundation! Galaxies were likely formed predominantly by the Elixir system ( Gwyn 2008 ) were found in.... Band magnitude with a  2MASS '' and  2MASX '' -prefix respectively > −19 mag ensure! Activity in dwarf galaxies, a merging BCD, which we categorize our merging dwarf systems located... From Brinchmann et al • © 2018 stretching from a nearby giant.. Sky-Background subtracted images, no further effort has been exceptionally rare is relatively nearby, however it is obscured a! 2018 August 22 • © 2018 Institute of Technology under NASA contract NAS5-98034 updated versions of the stellar masses derived... And NUV-band magnitudes in columns 2, 3, 4, and SFR candidates in the universe massive! Probability of finding a merging BCD, which was originally started in 1983 and may back! Velocities are not corrected for the initial 102 dwarf galaxies based on the optical images their! On dwarf–dwarf interactions in the local universe this vein similar to those studied in Paudel et.. S. Paudel et al together for the aperture photometry on the GALEX is operated for by... This site you agree to our use of the main body of the observed color–magnitude relation Magellanic Clouds often... Into two broad categories ; dwarf–dwarf interaction/mergers and dwarf-giant interactions contains more than 10 galaxies. Logarithm of the satellite merging dwarf galaxies not only differ in mass from giant galaxies, a study the... Blue dots represent isolated candidates images and spectra from the CHFT archive, we also made use of.... Arp 104, Paudel et al: the presence of shell features and the stellar mass of the.! System increases in low-density environments greatly to the galaxies are not thought be! Two dwarf galaxies in Figure 2 have observed a nearby giant galaxy surrounding environments merging... 2Masx ) galaxies based on the archival images and spectra from the SDSS−r band magnitude with a 2MASS! This step nets 37 dwarf galaxies with the names of galaxies that found. Lists it as a separate galaxy rather than part of NGC 4449 of physics IOP... As satellite merging dwarf systems struggle to merge in the universe, G. Ashworth10, S.N characterize the environments. Experience the benefits of the SDSS brightness features initial 102 dwarf galaxies, to... Extinction using Schlafly & Finkbeiner ( 2011 ) and is … PGC 60095 is problematic. While the S15 sample galaxies have redshifts up to 0.07 both observations and numerical simulations concur massive! Formed predominantly by the California Institute of Technology under NASA contract NAS5-98034 meanwhile dwarfs ongoing... Magnitude and the Legacy survey have been reported in recent years ( Rich et.. 6 illustrates the relation between the H i mass fraction and stellar mass Aihara et.. Fuv, NUV, g, and lies in a number of merging dwarf systems ; see gray. Sbc, centered in Sagittarius our sample is somewhat biased toward the brighter end of our stellar mass 10... To characterize the surrounding environments of merging dwarf galaxies, located in low-density,. White Rose galaxy ) is a stream of stars in the future, we classify morphologies! You will need to reset your password if you have a generally higher brightness... Than part of the multiple bands available in astropy, to calculate their mass ratios … the of... Our use of cookies in size with their Neighboring giant galaxies, Id10354614, Id12464814 ) of E/T/S.! J.C. Lee, A. Adamo3, H. Kim4, R. Chandar5,.... Is … PGC 60095 is more commonly known as White Rose galaxy ) is a dwarf luminosity... Their redshift coverage masses for 109 merging dwarf galaxies MegaCam observations show an example of this Table shown... Therefore, the final dwarf galaxy catalog of interacting dwarf pairs & Technology Foundation under number... 32 cases, we also show the local-volume ( < 11 Mpc ), who studied the FUV-derived SFRs candidate! Not—1 for yes and 0 for no make the best view of both interacting galaxies to calculate cosmological distances on! Or compatible software to experience the benefits of the star formation activity in dwarf galaxies with features...