A Correlated Search for Local Dwarf Galaxies in GALFA-HI and Pan-STARRS

Abstract

In recent years, ultrafaint dwarf (UFD) galaxies have been found through systematic searches of large optical surveys. However, the existence of Leo T, a nearby gas-rich dwarf, suggests that there could be other nearby UFDs that are optically obscured but have gas detectable at nonoptical wavelengths. With this in mind, we perform a search of the full Galactic Arecibo $L-$band Feed Array HI (GALFA-HI) survey, a radio survey which covers one-third of the sky at velocities $-650<V_{\mathrm{LSR}}<+650\mathrm{km}{\mathrm{s}}^{-1}$, for neutral hydrogen sources. We are able to probe regions of the sky at lower Galactic latitudes and smaller $|V_{LSR}|$ compared to previous explorations. We use the Source Finding Application (SoFiA) on GALFA-HI and select all sources with similar properties to Leo T and other local dwarf galaxies. We find 690 dwarf galaxy candidates, one of which is particularly promising and likely a new galaxy near the Galactic plane ($b=-8^{\circ }$) that is comparable in velocity width and HI-flux to other recently discovered local volume galaxies. We find we are sensitive to Leo T-like objects out to $1\mathrm{Mpc}$ at velocities clear from background HI emission. We check each candidate's corresponding optical fields from Pan-STARRS and fit stars drawn from isochrones, but find no evidence of stellar populations. We thus find no other Leo T-like dwarfs within $500\mathrm{kpc}$ of the Milky Way in the one-third of the sky covered by the GALFA-HI footprint and discuss our nondetection in a cosmological context.

arXiv commentAccepted to ApJ. 14 pages, 10 figures. Table 2 is available in its entirety as an ancillary file on this page

References in corpus (42)

• The NumPy array: a structure for efficient numerical computation
• PARSEC: stellar tracks and isochrones with the PAdova and TRieste Stellar Evolution Code
• Binary companions of evolved stars in APOGEE DR14: Search method and catalog of ~5,000 companions
• Where are the missing galactic satellites?
• The observed properties of dwarf galaxies in and around the Local Group
• The Kinematics of the Ultra-Faint Milky Way Satellites: Solving the Missing Satellite Problem
• Cats and Dogs, Hair and A Hero: A Quintet of New Milky Way Companions
• Improving PARSEC models for very low mass stars
• PARSEC evolutionary tracks of massive stars up to $350M_{\odot }$ at metallicities 0.0001$\le Z\le$0.04
• Eight New Milky Way Companions Discovered in First-Year Dark Energy Survey Data
• The Arecibo Legacy Fast ALFA Survey: The ALFALFA Extragalactic HI Source Catalog
• A New Milky Way Dwarf Galaxy in Ursa Major
• New PARSEC evolutionary tracks of massive stars at low metallicity: testing canonical stellar evolution in nearby star forming dwarf galaxies
• A Faint New Milky Way Satellite in Bootes
• HI in Local Group Dwarf Galaxies and Stripping by the Galactic Halo
• Hundreds of Milky Way Satellites? Luminosity Bias in the Satellite Luminosity Function
• A Curious New Milky Way Satellite in Ursa Major
• The Quenching of the Ultra-Faint Dwarf Galaxies in the Reionization Era
• Discovery of an Unusual Dwarf Galaxy in the Outskirts of the Milky Way
• SoFiA: a flexible source finder for 3D spectral line data
• Gaia DR2 Proper Motions of Dwarf Galaxies within 420 kpc: Orbits, Milky Way Mass, Tidal Influences, Planar Alignments, and Group Infall
• Formation Histories of Dwarf Galaxies in the Local Group
• The Local Group on FIRE: Dwarf galaxy populations across a suite of hydrodynamic simulations
• The GALFA-HI Survey: Data Release 1
• The Star Formation Histories of Local Group Dwarf Galaxies II. Searching For Signatures of Reionization
• The Invisibles: A Detection Algorithm to Trace the Faintest Milky Way Satellites
• The Dearth of Neutral Hydrogen in Galactic Dwarf Spheroidal Galaxies
• Leo P: An Unquenched Very Low-Mass Galaxy
• The total satellite population of the Milky Way
• Abundance of Field Galaxies
• Too Many, Too Few, or Just Right? The Predicted Number and Distribution of Milky Way Dwarf Galaxies
• A Catalog of Ultra-compact High Velocity Clouds from the ALFALFA Survey: Local Group Galaxy Candidates?
• A Common Origin for Globular Clusters and Ultra-faint Dwarfs in Simulations of the First Galaxies
• The Arecibo Legacy Fast ALFA Survey: VI. Second HI Source Catalog of the Virgo Cluster Region
• Gas Loss by Ram Pressure Stripping and Internal Feedback From Low Mass Milky Way Satellites
• Gas depletion in Local Group dwarfs on ~250 kpc scales: Ram pressure stripping assisted by internal heating at early times
• The GALFA-HI Compact Cloud Catalog
• Late Gas accretion onto Primordial Minihalos: a Model for Leo T, Dark Galaxies and Extragalactic High-Velocity Clouds
• Deep neutral hydrogen observations of Leo T with the Westerbork Synthesis Radio Telescope
• Where are All the Gas-Bearing Local Dwarf Galaxies? Quantifying Possible Impacts of Reionization
• HST Imaging of the Local Volume Dwarf Galaxies Pisces A&B: Prototypes for Local Group Dwarfs
• Finding gas-rich dwarf galaxies betrayed by their ultraviolet emission

Cited by in corpus (4)

• WALLABY -- An SKA Pathfinder HI Survey
• The Gas Content and Stripping of Local Group Dwarf Galaxies
• EDGE: From quiescent to gas-rich to star-forming low-mass dwarf galaxies
• A Search for Gas-Rich Dwarf Galaxies in the Local Universe with ALFALFA and the WIYN One Degree Imager