NASA/IPAC EXTRAGALACTIC DATABASE
Date and Time of the Query: 2019-05-23 T14:33:34 PDT
Help | Comment | NED Home

For refcode 2012ApJ...757...84W:
Retrieve 31 NED objects in this reference.
Please click here for ADS abstract

NED Abstract

Copyright by American Astronomical Society. Reproduced by permission
2012ApJ...757...84W Tracing Cold H I Gas in nearby, Low-mass Galaxies Warren, Steven R.; Skillman, Evan D.; Stilp, Adrienne M.; Dalcanton, Julianne J.; Ott, Jurgen; Walter, Fabian; Petersen, Eric A.; Koribalski, Barbel; West, Andrew A. Abstract. We analyze line-of-sight atomic hydrogen (H I) line profiles of 31 nearby, low-mass galaxies selected from the Very Large Array---ACS Nearby Galaxy Survey Treasury (VLA-ANGST) and The H I Nearby Galaxy Survey (THINGS) to trace regions containing cold (T <~ 1400 K) H I from observations with a uniform linear scale of 200 pc beam^-1^. Our galaxy sample spans four orders of magnitude in total H I mass and nine magnitudes in M_B_ . We fit single and multiple component functions to each spectrum to isolate the cold, neutral medium given by a low-dispersion (<6 km s^-1^) component of the spectrum. Most H I spectra are adequately fit by a single Gaussian with a dispersion of 8-12 km s^-1^. Cold H I is found in 23 of 27 (~85%) galaxies after a reduction of the sample size due to quality-control cuts. The cold H I contributes ~20% of the total line-of-sight flux when found with warm H I. Spectra best fit by a single Gaussian, but dominated by cold H I emission (i.e., have velocity dispersions of <6 km s^-1^), are found primarily beyond the optical radius of the host galaxy. The cold H I is typically found in localized regions and is generally not coincident with the very highest surface density peaks of the global H I distribution (which are usually areas of recent star formation). We find a lower limit for the mass fraction of cold-to-total H I gas of only a few percent in each galaxy. Key words: galaxies: dwarf, galaxies: ISM, ISM: atoms, ISM: clouds, ISM: structure, radio lines: ISM
Retrieve 31 NED objects in this reference.
Please click here for ADS abstract

Back to NED Home