Extended far-ultraviolet emission in distant dwarf galaxies

Abstract

Blue Compact Dwarfs (BCDs) are low-luminosity (M${}_K>-21$ mag), metal-poor ($\frac{1}{50}$ $\le Z/Z_{\odot }\le \frac{1}{2}$), centrally concentrated galaxies with bright clumps of star-formation. Cosmological surface brightness dimming and small size limit their detection at high redshifts, making their formation process difficult to observe. Observations of BCDs are needed at intermediate redshifts, where they are still young enough to show their formative stages, particularly in the outer regions where cosmic gas accretion should drive evolution. Here, we report the discovery of excess far-ultraviolet (FUV) emission in the outer regions of 11 BCDs in the GOODS-South field at redshifts between 0.1 and 0.24, corresponding to look back times of 1.3 - 2.8 Gyr in standard cosmology. These observations were made by the Ultra-Violet Imaging Telescope (UVIT) on AstroSat. For ten BCDs, the radial profiles of intrinsic FUV emission, corrected for the instrument point spread function, have larger scale-lengths than their optical counterparts observed with the Hubble Space Telescope. Such shallow FUV profiles suggest extended star-formation in cosmically accreting disks. Clumpy structure in the FUV also suggests the outer FUV disks are gravitationally unstable. Dynamical friction on the clumps drives them inward at an average rate exceeding $10^6{M}_{\odot }$Gyr${}^{-1}$.

arXiv comment23 pages, 7 Figures, 5 Tables. Published on 20th July, 2022, by Nature

References in corpus (39)

• Maps of Dust IR Emission for Use in Estimation of Reddening and CMBR Foregrounds
• Measuring Reddening with SDSS Stellar Spectra and Recalibrating SFD
• The Dust Content and Opacity of Actively Star-Forming Galaxies
• Starburst99: Synthesis Models for Galaxies with Active Star Formation
• Star Formation in the Milky Way and Nearby Galaxies
• Stellar mass-to-light ratios and the Tully-Fisher relation
• 3D-HST WFC3-selected Photometric Catalogs in the Five CANDELS/3D-HST Fields: Photometry, Photometric Redshifts and Stellar Masses
• The 3D-HST Survey: Hubble Space Telescope WFC3/G141 grism spectra, redshifts, and emission line measurements for $\sim 100,000$ galaxies
• Little Things
• A Search for Extended Ultraviolet Disk (XUV-disk) Galaxies in the Local Universe
• The most metal-poor galaxies
• Palomar/Las Campanas Imaging Atlas of Blue Compact Dwarf galaxies: I. Images and integrated photometry
• CANDELS Multiwavelength catalogs: Source Identification and Photometry in the CANDELS UKIDSS Ultra-Deep Survey Field
• ALMA Spectroscopic Survey in the Hubble Ultra Deep Field: The Infrared Excess of UV-selected z=2-10 galaxies as a function of UV-continuum Slope and Stellar Mass
• The Outer Disks of Early-Type Galaxies. I. Surface-Brightness Profiles of Barred Galaxies
• The HDUV Survey: A Revised Assessment of the Relationship between UV Slope and Dust Attenuation for High-Redshift Galaxies
• Broad-Band Imaging of a Large Sample of Irregular Galaxies
• Clumpy Galaxies in GOODS and GEMS: Massive Analogs of Local Dwarf Irregulars
• Outside-in Shrinking of the Star-forming Disk of Dwarf Irregular Galaxies
• Abundant molecular gas and inefficient star formation in intracluster regions: Ram pressure stripped tail of the Norma galaxy ESO137-001
• GALEX Ultraviolet Imaging of Dwarf Galaxies and Star Formation
• The blue compact dwarf galaxy I Zw 18: a comparative study of its low-surface-brightness component
• The Hawk-I UDS and GOODS Survey (HUGS): Survey design and deep K-band number counts
• Number Counts of GALEX Sources in FUV (1530A) and NUV (2310A) Bands
• In-orbit Performance of UVIT and First Results
• Surface Brightness Profiles of Dwarf Galaxies: I. Profiles and Statistics
• The GALEX Ultraviolet Virgo Cluster Survey (GUViCS). II. Constraints on star formation in ram-pressure stripped gas
• In-spiraling Clumps in Blue Compact Dwarf Galaxies
• AstroSat detection of Lyman continuum emission from a z=1.42 galaxy
• The Outer Disks of Dwarf Irregular Galaxies
• $Profiler$ - A Fast and Versatile New Program for Decomposing Galaxy Light Profiles
• A Stellar Population Gradient in VII Zw 403 - Implications for the Formation of Blue Compact Dwarf Galaxies
• The Dust Attenuation Curve versus Stellar Mass for Emission Line Galaxies at z ~ 2
• CO map and steep Kennicutt-Schmidt relation in the extended UV disk of M63
• The source of leaking ionizing photons from Haro11 -- Clues from HST/COS spectroscopy of knots A, B and C
• The Effect of Surface Brightness Dimming in the Selection of High-z Galaxies
• Near-Infrared Survey of the GOODS-North Field: Search for Luminous Galaxy Candidates at z=>6.5
• Surface brightness profiles of blue compact dwarf galaxies in the GOODS-N and GOODS-S field
• ALMA CO(2-1) observations in the XUV disk of M83

Cited by in corpus (1)

• What drives the wheels of evolution in NGC 1512? A UVIT study