The NIBLES bivariate luminosity-H I mass distribution function revised using Arecibo follow-up observations
Abstract
We present a modified optical luminosity-H I mass bivariate luminosity function based on H I line observations from the Nançay Interstellar Baryons Legacy Extragalactic Survey (NIBLES), including data from our new, four times more sensitive follow-up H I line observations obtained with the Arecibo radio telescope. The follow-up observations were designed to probe the underlying H I mass distribution of the NIBLES galaxies that were undetected or marginally detected in H I at the Nançay Radio Telescope. Our total follow-up sample consists of 234 galaxies, and it spans the entire luminosity and color range of the parent NIBLES sample of 2600 nearby (900 < cz < 12 000 km s-1) SDSS galaxies. We incorporated the follow-up data into the bivariate analysis by scaling the NIBLES undetected fraction by an Arecibo-only distribution. We find the resulting increase in low H I mass-to-light ratio densities to be about 10% for the bins -1.0 ≤ log(MHI/M⊙/Lr/L⊙) ≤ -0.5, which produces an increased H I mass function (HIMF) low mass slope of α = -1.14 ± 0.07, being slightly shallower than the values of -1.35 ± 0.05 obtained by recent blind H I surveys. Applying the same correction to the optically corrected bivariate luminosity function from our previous paper produces a larger density increase of about 0.5 to 1 dex in the lowest H I mass-to-light ratio bins for a given luminosity while having a minimal effect on the resulting HIMF low mass slope, which still agrees with blind survey HIMFs. This indicates that while low H I-mass-to-light ratio galaxies do not contribute much to the one-dimensional HIMF, their inclusion has a significant impact on the densities in the two-dimensional distribution.
Tables A.1 and A.2, along with the Hi line spectra are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/642/A175- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- October 2020
- DOI:
- 10.1051/0004-6361/202037711
- arXiv:
- arXiv:2008.05077
- Bibcode:
- 2020A&A...642A.175B
- Keywords:
-
- galaxies: statistics;
- galaxies: general;
- galaxies: formation;
- galaxies: dwarf;
- radio lines: galaxies;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- 20 pages, 18 figures