%0 Generic %1 tollerud2014local %A Tollerud, Erik J. %A Geha, Marla C. %A Grcevich, Jana %A Putman, Mary E. %A Stern, Daniel %D 2014 %K HI dwarf local volume %T Two Local Volume Dwarf Galaxies Discovered in 21 cm Emission: Pisces A and B %U http://arxiv.org/abs/1411.5019 %X We report the discovery of two dwarf galaxies, Pisces A and B, from a blind 21 cm HI search. These were the only two galaxies found via optical imaging and spectroscopy of 22 HI clouds identified in the GALFA-HI survey as dwarf galaxy candidates. They have properties consistent with being in the Local Volume ($<10$ Mpc), and one has resolved stellar populations such that it may be on the outer edge of the Local Group ($1 \, Mpc$ from M31). While the distance uncertainty makes interpretation ambiguous, these may be among the faintest starforming galaxies known. Additionally, rough estimates comparing these galaxies to $Łambda$CDM dark matter simulations suggest consistency in number density, implying that dark matter halos likely to host these galaxies are primarily HI-rich. The galaxies may thus be indicative of a large population of dwarfs at the limit of detectability that are comparable to the faint satellites of the Local Group. Because they are outside the influence of a large dark matter halo to alter their evolution, these galaxies can provide critical anchors to dwarf galaxy formation models.

@misc{tollerud2014local, abstract = {We report the discovery of two dwarf galaxies, Pisces A and B, from a blind 21 cm HI search. These were the only two galaxies found via optical imaging and spectroscopy of 22 HI clouds identified in the GALFA-HI survey as dwarf galaxy candidates. They have properties consistent with being in the Local Volume ($<10$ Mpc), and one has resolved stellar populations such that it may be on the outer edge of the Local Group ($\sim 1 \, {\rm Mpc}$ from M31). While the distance uncertainty makes interpretation ambiguous, these may be among the faintest starforming galaxies known. Additionally, rough estimates comparing these galaxies to $\Lambda$CDM dark matter simulations suggest consistency in number density, implying that dark matter halos likely to host these galaxies are primarily HI-rich. The galaxies may thus be indicative of a large population of dwarfs at the limit of detectability that are comparable to the faint satellites of the Local Group. Because they are outside the influence of a large dark matter halo to alter their evolution, these galaxies can provide critical anchors to dwarf galaxy formation models.}, added-at = {2014-11-20T10:14:15.000+0100}, author = {Tollerud, Erik J. and Geha, Marla C. and Grcevich, Jana and Putman, Mary E. and Stern, Daniel}, biburl = {https://www.bibsonomy.org/bibtex/2f8507d11ce4d88f4e4ec27ee55f557c0/miki}, description = {[1411.5019] Two Local Volume Dwarf Galaxies Discovered in 21 cm Emission: Pisces A and B}, interhash = {0b27f89c5c70049857705835a8fde9b1}, intrahash = {f8507d11ce4d88f4e4ec27ee55f557c0}, keywords = {HI dwarf local volume}, note = {cite arxiv:1411.5019Comment: 6 pages, 3 figures, ApJL submitted (referee comments included)}, timestamp = {2014-11-20T10:14:15.000+0100}, title = {Two Local Volume Dwarf Galaxies Discovered in 21 cm Emission: Pisces A and B}, url = {http://arxiv.org/abs/1411.5019}, year = 2014 }