A diffuse tidal dwarf galaxy destined to fade out as a "dark galaxy"
Affiliation
Steward Observatory, University of ArizonaIssue Date
2021
Metadata
Show full item recordPublisher
EDP SciencesCitation
Román, J., Jones, M. G., Montes, M., Verdes-Montenegro, L., Garrido, J., & Sánchez, S. (2021). A diffuse tidal dwarf galaxy destined to fade out as a “dark galaxy.” Astronomy and Astrophysics, 649.Journal
Astronomy and AstrophysicsRights
© ESO 2021.Collection Information
This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.Abstract
We have explored the properties of a peculiar object detected in deep optical imaging and located at the tip of an H » I tail emerging from Hickson Compact Group 16. Using multiband photometry from infrared to ultraviolet, we were able to constrain its stellar age to 58-9+22 Myr with a rather high metallicity of [Fe/H] = -0.16-0.41+0.43 for its stellar mass of M- = 4.2 × 106 Mpdbl, a typical signature of tidal dwarf galaxies. The structural properties of this object are similar to those of diffuse galaxies, with a round and featureless morphology, a large effective radius (reff = 1.5 kpc), and a low surface brightness (μg-eff = 25.6 mag arcsec-2). Assuming that the object is dynamically stable and able to survive in the future, its fading in time via the aging of its stellar component will make it undetectable in optical observations in just ∼2 Gyr of evolution, even in the deepest current or future optical surveys. Its high H » I mass, M(HI) = 3.9 × 108 Mpdbl, and future undetectable stellar component will make the object match the observational properties of dark galaxies, that is, dark matter halos that failed to turn gas into stars. Our work presents further observational evidence of the feasibility of H » I tidal features becoming fake dark galaxies; it also shows the impact of stellar fading, particularly in high metallicity systems such as tidal dwarfs, in hiding aged stellar components beyond detection limits in optical observations. © ESO 2021.Note
Immediate accessISSN
0004-6361Version
Final published versionae974a485f413a2113503eed53cd6c53
10.1051/0004-6361/202141001
Scopus Count
Collections
Related items
Showing items related by title, author, creator and subject.
-
The Faint End of the Centaurus A Satellite Luminosity FunctionCrnojević, D.; Sand, D. J.; Bennet, P.; Pasetto, S.; Spekkens, K.; Caldwell, N.; Guhathakurta, P.; McLeod, B.; Seth, A.; Simon, J. D.; et al. (IOP PUBLISHING LTD, 2019-02-10)The Panoramic Imaging Survey of Centaurus and Sculptor (PISCeS) is constructing a wide-field map of the resolved stellar populations in the extended halos of these two nearby, prominent galaxies. We present new Magellan/Megacam imaging of a similar to 3 deg(2) area around Centaurus A (Cen A), which filled in much of our coverage to its south, leaving a nearly complete halo map out to a projected radius of similar to 150 kpc and allowing us to identify two new resolved dwarf galaxies. We have additionally obtained deep Hubble Space Telescope (HST) optical imaging of 11 out of the 13 candidate dwarf galaxies identified around Cen A and presented in Crnojevic et al. 2016a: seven are confirmed to be satellites of Cen A, while four are found to be background galaxies. We derive accurate distances, structural parameters, luminosities, and photometric metallicities for the seven candidates confirmed by our HST/ACS imaging. We further study the stellar population along the similar to 60 kpc long (in projection) stream associated with Dw3, which likely had an initial brightness of M-V similar to -15 and shows evidence for a metallicity gradient along its length. Using the total sample of 11 dwarf satellites discovered by the PISCeS survey, as well as 13 brighter previously known satellites of Cen A, we present a revised galaxy luminosity function for the Cen A group down to a limiting magnitude of M-V similar to -8, which has a slope of -1.14 +/- 0.17, comparable to that seen in the Local Group and in other nearby groups of galaxies.
-
Nuclear starburst activity induced by elongated bulges in spiral galaxiesKim, Eunbin; Kim, Sungsoo S; Choi, Yun-Young; Lee, Gwang-Ho; de Grijs, Richard; Lee, Myung Gyoon; Hwang, Ho Seong; Univ Arizona, Steward Observ (OXFORD UNIV PRESS, 2018-06-05)We study the effects of bulge elongation on the star formation activity in the centres of spiral galaxies using the data from the Sloan Digital Sky Survey Data Release 7. We construct a volume-limited sample of face-on spiral galaxies with Mr < −19.5 mag at 0.02 ≤ z < 0.055 by excluding barred galaxies, where the aperture of the SDSS spectroscopic fibre covers the bulges of the galaxies. We adopt the ellipticity of bulges measured by Simard et al., who performed two-dimensional bulge + disc decompositions using the SDSS images of galaxies, and identify nuclear starbursts using the fibre specific star formation rates derived from the SDSS spectra. We find a statistically significant correlation between bulge elongation and nuclear starbursts in the sense that the fraction of nuclear starbursts increases with bulge elongation. This correlation is more prominent for fainter and redder galaxies, which exhibit higher ratios of elongated bulges. We find no significant environmental dependence of the correlation between bulge elongation and nuclear starbursts. These results suggest that non-axisymmetric bulges can efficiently feed the gas into the centre of galaxies to trigger nuclear starburst activity.
-
Exploring the dust content of galactic winds with Herschel – II. Nearby dwarf galaxiesMcCormick, Alexander; Veilleux, Sylvain; Meléndez, Marcio; Martin, Crystal L; Bland-Hawthorn, Joss; Cecil, Gerald; Heitsch, Fabian; Müller, Thomas; Rupke, David S N; Engelbracht, Chad; et al. (OXFORD UNIV PRESS, 2018-06)We present the results from an analysis of deep Herschel Space Observatory observations of six nearby dwarf galaxies known to host galactic-scale winds. The superior far-infrared sensitivity and angular resolution of Herschel have allowed detection of cold circumgalactic dust features beyond the stellar components of the host galaxies traced by Spitzer 4.5 mu m images. Comparisons of these cold dust features with ancillary data reveal an imperfect spatial correlation with the ionized gas and warm dust wind components. We find that typically similar to 10-20 per cent of the total dust mass in these galaxies resides outside of their stellar discs, but this fraction reaches similar to 60 per cent in the case of NGC 1569. This galaxy also has the largest metal-licity (O/H) deficit in our sample for its stellar mass. Overall, the small number of objects in our sample precludes drawing strong conclusions on the origin of the circumgalactic dust. We detect no statistically significant trends with star formation properties of the host galaxies, as might be expected if the dust were lifted above the disc by energy inputs from ongoing star formation activity. Although a case for dust entrained in a galactic wind is seen in NGC 1569, in all cases, we cannot rule out the possibility that some of the circumgalactic dust might be associated instead with gas accreted or removed from the disc by recent galaxy interaction events, or that it is part of the outer gas-rich portion of the disc that lies below the sensitivity limit of the Spitzer 4.5 mu m data.