The HI Mass Function of the Local Universe: Combining Measurements from HIPASS, ALFALFA and FASHI

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Main Authors: Ma, Wenlin, Guo, Hong, Xu, Haojie, Jones, Michael G., Zhang, Chuan-Peng, Zhu, Ming, Wang, Jing, Wang, Jie, Jiang, Peng
Format: Preprint
Published: 2024
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author Ma, Wenlin
Guo, Hong
Xu, Haojie
Jones, Michael G.
Zhang, Chuan-Peng
Zhu, Ming
Wang, Jing
Wang, Jie
Jiang, Peng
author_facet Ma, Wenlin
Guo, Hong
Xu, Haojie
Jones, Michael G.
Zhang, Chuan-Peng
Zhu, Ming
Wang, Jing
Wang, Jie
Jiang, Peng
contents We present the first HI mass function (HIMF) measurement for the recent FAST All Sky HI (FASHI) survey and the most complete measurements of HIMF in the local universe thus far. We obtained these results by combining the HI catalogues from HI Parkes All Sky Survey (HIPASS), Arecibo Legacy Fast ALFA (ALFALFA) and FASHI surveys at redshift 0 < z < 0.05, covering 76% of the entire sky. We adopted the same methods to estimate the distances, calculate the sample completeness, and determine the HIMF for all three surveys. The best-fit Schechter function for the total HIMF shows a low-mass slope parameter of alpha = -1.30 and a knee mass log(Ms) = 9.86, along with a normalisation of phi_s = 0.00658. This gives us the cosmic HI abundance: omega_HI= 0.000454. We find that a double Schechter function with the same slope alpha better describes our HIMF, where the two different knee masses are log(Ms1) = 9.96 and log(Ms2) = 9.65. We verify that the measured HIMF is marginally affected by the choice of distance estimates. The effect of cosmic variance is significantly suppressed by combining the three surveys and this provides a unique opportunity to obtain an unbiased estimate of the HIMF in the Local Universe.
format Preprint
id arxiv_https___arxiv_org_abs_2411_09903
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle The HI Mass Function of the Local Universe: Combining Measurements from HIPASS, ALFALFA and FASHI
Ma, Wenlin
Guo, Hong
Xu, Haojie
Jones, Michael G.
Zhang, Chuan-Peng
Zhu, Ming
Wang, Jing
Wang, Jie
Jiang, Peng
Astrophysics of Galaxies
We present the first HI mass function (HIMF) measurement for the recent FAST All Sky HI (FASHI) survey and the most complete measurements of HIMF in the local universe thus far. We obtained these results by combining the HI catalogues from HI Parkes All Sky Survey (HIPASS), Arecibo Legacy Fast ALFA (ALFALFA) and FASHI surveys at redshift 0 < z < 0.05, covering 76% of the entire sky. We adopted the same methods to estimate the distances, calculate the sample completeness, and determine the HIMF for all three surveys. The best-fit Schechter function for the total HIMF shows a low-mass slope parameter of alpha = -1.30 and a knee mass log(Ms) = 9.86, along with a normalisation of phi_s = 0.00658. This gives us the cosmic HI abundance: omega_HI= 0.000454. We find that a double Schechter function with the same slope alpha better describes our HIMF, where the two different knee masses are log(Ms1) = 9.96 and log(Ms2) = 9.65. We verify that the measured HIMF is marginally affected by the choice of distance estimates. The effect of cosmic variance is significantly suppressed by combining the three surveys and this provides a unique opportunity to obtain an unbiased estimate of the HIMF in the Local Universe.
title The HI Mass Function of the Local Universe: Combining Measurements from HIPASS, ALFALFA and FASHI
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2411.09903