(Almost) Dark Galaxies in the ALFALFA Survey: Isolated HI-bearing Ultra-diffuse Galaxies

Lukas Leisman, Martha P. Haynes, Steven Janowiecki, Gregory Hallenbeck, Gyula Jozsa, Riccardo Giovanelli, Elizabeth A. K. Adams, David Bernal Neira, John M. Cannon, William F. Janesh, Katherine L. Rhode, John J. Salzer

Research output: Contribution to journalArticle

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Abstract

We present a sample of 115 very low optical surface brightness, highly extended, H I-rich galaxies carefully selected from the ALFALFA survey that have similar optical absolute magnitudes, surface brightnesses, and radii to recently discovered "ultra-diffuse" galaxies (UDGs). However, these systems are bluer and have more irregular morphologies than other UDGs, are isolated, and contain significant reservoirs of H I. We find that while these sources have normal star formation rates for H I-selected galaxies of similar stellar mass, they have very low star formation efficiencies. We further present deep optical and H I-synthesis follow-up imaging of three of these H I-bearing ultra-diffuse sources. We measure H I diameters extending to similar to 40 kpc, but note that while all three sources have large H I diameters for their stellar mass, they are consistent with the H I mass-H I radius relation. We further analyze the H I velocity widths and rotation velocities for the unresolved and resolved sources, respectively, and find that the sources appear to inhabit halos of dwarf galaxies. We estimate spin parameters, and suggest that these sources may exist in high spin parameter halos, and as such may be potential H I-rich progenitors to the ultra-diffuse galaxies observed in cluster environments.

Original languageEnglish
Article number133
Number of pages17
JournalThe Astrophysical Journal
Volume842
Issue number2
DOIs
Publication statusPublished - 20 Jun 2017

Cite this

Leisman, L., Haynes, M. P., Janowiecki, S., Hallenbeck, G., Jozsa, G., Giovanelli, R., ... Salzer, J. J. (2017). (Almost) Dark Galaxies in the ALFALFA Survey: Isolated HI-bearing Ultra-diffuse Galaxies. The Astrophysical Journal, 842(2), [133]. https://doi.org/10.3847/1538-4357/aa7575
Leisman, Lukas ; Haynes, Martha P. ; Janowiecki, Steven ; Hallenbeck, Gregory ; Jozsa, Gyula ; Giovanelli, Riccardo ; Adams, Elizabeth A. K. ; Neira, David Bernal ; Cannon, John M. ; Janesh, William F. ; Rhode, Katherine L. ; Salzer, John J. / (Almost) Dark Galaxies in the ALFALFA Survey : Isolated HI-bearing Ultra-diffuse Galaxies. In: The Astrophysical Journal. 2017 ; Vol. 842, No. 2.
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title = "(Almost) Dark Galaxies in the ALFALFA Survey: Isolated HI-bearing Ultra-diffuse Galaxies",
abstract = "We present a sample of 115 very low optical surface brightness, highly extended, H I-rich galaxies carefully selected from the ALFALFA survey that have similar optical absolute magnitudes, surface brightnesses, and radii to recently discovered {"}ultra-diffuse{"} galaxies (UDGs). However, these systems are bluer and have more irregular morphologies than other UDGs, are isolated, and contain significant reservoirs of H I. We find that while these sources have normal star formation rates for H I-selected galaxies of similar stellar mass, they have very low star formation efficiencies. We further present deep optical and H I-synthesis follow-up imaging of three of these H I-bearing ultra-diffuse sources. We measure H I diameters extending to similar to 40 kpc, but note that while all three sources have large H I diameters for their stellar mass, they are consistent with the H I mass-H I radius relation. We further analyze the H I velocity widths and rotation velocities for the unresolved and resolved sources, respectively, and find that the sources appear to inhabit halos of dwarf galaxies. We estimate spin parameters, and suggest that these sources may exist in high spin parameter halos, and as such may be potential H I-rich progenitors to the ultra-diffuse galaxies observed in cluster environments.",
keywords = "galaxies: evolution, galaxies: star formation, radio lines: galaxies, SURFACE BRIGHTNESS GALAXIES, DIGITAL SKY SURVEY, FAST ALPHA SURVEY, STAR-FORMATION EFFICIENCY, I-RICH GALAXIES, IRREGULAR GALAXIES, NEARBY GALAXIES, VIRGO CLUSTER, COMA CLUSTER, MILKY-WAY",
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Leisman, L, Haynes, MP, Janowiecki, S, Hallenbeck, G, Jozsa, G, Giovanelli, R, Adams, EAK, Neira, DB, Cannon, JM, Janesh, WF, Rhode, KL & Salzer, JJ 2017, '(Almost) Dark Galaxies in the ALFALFA Survey: Isolated HI-bearing Ultra-diffuse Galaxies' The Astrophysical Journal, vol. 842, no. 2, 133. https://doi.org/10.3847/1538-4357/aa7575

(Almost) Dark Galaxies in the ALFALFA Survey : Isolated HI-bearing Ultra-diffuse Galaxies. / Leisman, Lukas; Haynes, Martha P.; Janowiecki, Steven; Hallenbeck, Gregory; Jozsa, Gyula; Giovanelli, Riccardo; Adams, Elizabeth A. K.; Neira, David Bernal; Cannon, John M.; Janesh, William F.; Rhode, Katherine L.; Salzer, John J.

In: The Astrophysical Journal, Vol. 842, No. 2, 133, 20.06.2017.

Research output: Contribution to journalArticle

TY - JOUR

T1 - (Almost) Dark Galaxies in the ALFALFA Survey

T2 - Isolated HI-bearing Ultra-diffuse Galaxies

AU - Leisman, Lukas

AU - Haynes, Martha P.

AU - Janowiecki, Steven

AU - Hallenbeck, Gregory

AU - Jozsa, Gyula

AU - Giovanelli, Riccardo

AU - Adams, Elizabeth A. K.

AU - Neira, David Bernal

AU - Cannon, John M.

AU - Janesh, William F.

AU - Rhode, Katherine L.

AU - Salzer, John J.

PY - 2017/6/20

Y1 - 2017/6/20

N2 - We present a sample of 115 very low optical surface brightness, highly extended, H I-rich galaxies carefully selected from the ALFALFA survey that have similar optical absolute magnitudes, surface brightnesses, and radii to recently discovered "ultra-diffuse" galaxies (UDGs). However, these systems are bluer and have more irregular morphologies than other UDGs, are isolated, and contain significant reservoirs of H I. We find that while these sources have normal star formation rates for H I-selected galaxies of similar stellar mass, they have very low star formation efficiencies. We further present deep optical and H I-synthesis follow-up imaging of three of these H I-bearing ultra-diffuse sources. We measure H I diameters extending to similar to 40 kpc, but note that while all three sources have large H I diameters for their stellar mass, they are consistent with the H I mass-H I radius relation. We further analyze the H I velocity widths and rotation velocities for the unresolved and resolved sources, respectively, and find that the sources appear to inhabit halos of dwarf galaxies. We estimate spin parameters, and suggest that these sources may exist in high spin parameter halos, and as such may be potential H I-rich progenitors to the ultra-diffuse galaxies observed in cluster environments.

AB - We present a sample of 115 very low optical surface brightness, highly extended, H I-rich galaxies carefully selected from the ALFALFA survey that have similar optical absolute magnitudes, surface brightnesses, and radii to recently discovered "ultra-diffuse" galaxies (UDGs). However, these systems are bluer and have more irregular morphologies than other UDGs, are isolated, and contain significant reservoirs of H I. We find that while these sources have normal star formation rates for H I-selected galaxies of similar stellar mass, they have very low star formation efficiencies. We further present deep optical and H I-synthesis follow-up imaging of three of these H I-bearing ultra-diffuse sources. We measure H I diameters extending to similar to 40 kpc, but note that while all three sources have large H I diameters for their stellar mass, they are consistent with the H I mass-H I radius relation. We further analyze the H I velocity widths and rotation velocities for the unresolved and resolved sources, respectively, and find that the sources appear to inhabit halos of dwarf galaxies. We estimate spin parameters, and suggest that these sources may exist in high spin parameter halos, and as such may be potential H I-rich progenitors to the ultra-diffuse galaxies observed in cluster environments.

KW - galaxies: evolution

KW - galaxies: star formation

KW - radio lines: galaxies

KW - SURFACE BRIGHTNESS GALAXIES

KW - DIGITAL SKY SURVEY

KW - FAST ALPHA SURVEY

KW - STAR-FORMATION EFFICIENCY

KW - I-RICH GALAXIES

KW - IRREGULAR GALAXIES

KW - NEARBY GALAXIES

KW - VIRGO CLUSTER

KW - COMA CLUSTER

KW - MILKY-WAY

U2 - 10.3847/1538-4357/aa7575

DO - 10.3847/1538-4357/aa7575

M3 - Article

VL - 842

JO - The Astrophysical Journal

JF - The Astrophysical Journal

SN - 0004-637X

IS - 2

M1 - 133

ER -

Leisman L, Haynes MP, Janowiecki S, Hallenbeck G, Jozsa G, Giovanelli R et al. (Almost) Dark Galaxies in the ALFALFA Survey: Isolated HI-bearing Ultra-diffuse Galaxies. The Astrophysical Journal. 2017 Jun 20;842(2). 133. https://doi.org/10.3847/1538-4357/aa7575