Multiwavelength Observations of Low Redshift Gas Rich Galaxies by Nishikanta Khandai

Value of the Information & Strength of the Argument

The talk provides significant value by presenting an unbiased method to construct H1-selected stellar mass functions and derive intrinsic scaling relations between H1 mass and stellar mass. The argumentation is meticulous, emphasizing the role of selection functions and demonstrating consistency with independent estimates (e.g., MIGHTEE, GAMA). The speaker transparently discusses uncertainties and assumptions, such as the choice of stellar mass estimates and the treatment of centrals vs. satellites. The stepwise maximum likelihood method and effective volume mapping show methodological sophistication.

Scientific Rigor, Source Quality, Title Accuracy

The speaker references specific surveys (ALFALFA, SDSS, MIGHTEE) and published papers, and the program link (ICTs workshop) is provided. The work appears rigorous, with validation against previous results and external data. The title is accurate, though it could be more specific about the H1-halo connection. The presentation is well-structured, and the speaker handles questions with clarity.

The title accurately reflects the talk's focus on multi-wavelength observations of low-redshift gas-rich galaxies, though the specific H1-halo connection is the core topic.

8/10

The presentation is based on peer-reviewed research, employs rigorous statistical methods (2D stepwise maximum likelihood, selection function corrections), and cross-validates results against independent data (e.g., MIGHTEE, GAMA). The speaker is a recognized expert, and the work involves current large surveys (ALFALFA, SDSS).

Markers derived by PSI from the transcript: the creator did not define chapters.

• 01:00Introduction to H1 history and motivation for studying gas-rich galaxies.
• 05:00Description of ALFALFA and SDSS joint catalog, including selection cuts and sample definition.
• 10:00Construction of H1 and stellar mass functions, and treatment of selection effects.
• 15:00Derivation of intrinsic scaling relations and comparison with MIGHTEE and volume-limited samples.
• 20:00Predictions for clustering using abundance matching and comparison with ALFALFA clustering.
• 25:00Discussion of future prospects with upcoming surveys (FAST, 4MOST) and concluding remarks.

• The Concurrence of Mega-Surveys workshop program — The talk was presented at this workshop; the program link provides additional context and list of organizers.

• ALFALFA survey — The Arecibo Legacy Fast ALFA survey provides blind H1 detections used in this analysis.
• SDSS — The Sloan Digital Sky Survey supplies optical photometry and spectroscopy used for stellar mass estimates and sample selection.

• Stellar mass estimate discrepancies — Different stellar mass estimates (Taylor, K-correct, GSWLC) show systematic differences at high masses, which the speaker addresses by recalibrating to a common reference.