Journal article
The Enigmatic (Almost) Dark Galaxy Coma P: Distance Measurement and Stellar Populations from HST Imaging
The Astronomical journal, Vol.157(2), p.76
02/01/2019
DOI: 10.3847/1538-3881/aafb39
Abstract
We present Hubble Space Telescope (HST) observations of the low surface brightness (SB) galaxy Coma P. This system was first discovered in the Arecibo Legacy Fast ALFA H I survey and was cataloged as an (almost) dark galaxy because it did not exhibit any obvious optical counterpart in the available survey data (e.g., Sloan Digital Sky Survey). Subsequent WIYN pODI imaging revealed an ultra-low SB stellar component located at the center of the H I detection. We use the HST images to produce a deep color-magnitude diagram of the resolved stellar population present in Coma P. We clearly detect a red stellar sequence that we interpret to be a red giant branch and use it to infer a tip of the red giant branch distance of 5.50(-0.53)(+0.28) Mpc. The new distance is substantially lower than earlier estimates and shows that Coma P is an extreme dwarf galaxy. Our derived stellar mass is only 4.3 x 10(5) M-circle dot, meaning that Coma P has an extreme H I-to-stellar mass ratio of 81. We present a detailed analysis of the galaxy environment within which Coma P resides. We hypothesize that Coma P formed within a local void and has spent most of its lifetime in a low-density environment. Over time, the gravitational attraction of the galaxies located in the void wall has moved it to the edge, where it had a recent "fly-by" interaction with M64. We investigate the possibility that Coma P is at a farther distance and conclude that the available data are best fit by a distance of 5.5 Mpc.
Details
- Title: Subtitle
- The Enigmatic (Almost) Dark Galaxy Coma P: Distance Measurement and Stellar Populations from HST Imaging
- Creators
- Samantha W. Brunker - Indiana University BloomingtonKristen B. W. Mcquinn - The University of Texas at AustinJohn J. Salzer - Indiana University BloomingtonJohn M. Cannon - Macalester CollegeSteven Janowiecki - International Centre for Radio Astronomy ResearchLukas Leisman - Valparaiso UniversityKatherine L. Rhode - Indiana University BloomingtonElizabeth A. K. Adams - University of GroningenCatherine Ball - Macalester CollegeAndrew E. Dolphin - RTXRiccardo Giovanelli - Cornell UniversityMartha P. Haynes - Cornell University
- Resource Type
- Journal article
- Publication Details
- The Astronomical journal, Vol.157(2), p.76
- Publisher
- IOP Publishing Ltd
- DOI
- 10.3847/1538-3881/aafb39
- ISSN
- 0004-6256
- eISSN
- 1538-3881
- Number of pages
- 15
- Grant note
- GO-14108 / NASA through a grant from the Space Telescope Science Institute; Space Telescope Science Institute AST-1615483 / NSF Astronomy & Astrophysics grant AST-1211683; AST-0607007; AST-1107390; AST-1714828 / NSF; National Science Foundation (NSF) NAS 5-26555 / NASA; National Aeronautics & Space Administration (NASA) DP150101734 / Australian Research Councils Discovery Project; Australian Research Council Brinson Foundation College of Arts and Sciences at Indiana University
- Language
- English
- Date published
- 02/01/2019
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984627302802771
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