NIBLES – an HI census of stellar mass selected SDSS galaxies

II. Arecibo follow-up HI observations^⋆

¹ University of Massachusetts, Astronomy Program, LGRT-B 619E, Amherst, MA 01003, USA
e-mail: zbutcher@astro.umass.edu
² GEPI, Observatoire de Paris, CNRS, Université Paris Diderot, 5 place Jules Janssen, 92190 Meudon, France
³ Station de Radioastronomie de Nançay, Observatoire de Paris, CNRS/INSU USR 704, Université d’Orléans OSUC, route de Souesmes, 18330 Nançay, France
⁴ Institut d’Astrophysique de Paris, UMR 7095, CNRS, Université Pierre et Marie Curie, 98bis boulevard Arago, 75014 Paris, France
⁵ Arecibo Observatory, National Astronomy and Ionosphere Center, Arecibo, PR 00612, USA

Received: 25 January 2016
Accepted: 10 July 2016

Abstract

We obtained Arecibo Hi line follow-up observations of 154 of the 2600 galaxies in the Nançay Interstellar Baryons Legacy Extragalactic Survey (NIBLES) sample. These observations are on average four times more sensitive than the original observations at the Nançay Radio Telescope. The main goal of this survey is to characterize the underlying Hi properties of the NIBLES galaxies which were undetected or marginally detected at Nançay. Of the Nançay non-detections, 85% were either clearly or marginally detected at Arecibo, while 89% of the Nançay marginal detections were clearly detected. Based on the statistics of the detections relative to g−i color and r-band luminosity (L_r) distribution among our Arecibo observations, we anticipate ~60% of our 867 Nançay non-detections and marginal detections could be detected at the sensitivity of our Arecibo observations. Follow-up observations of our low luminosity (L_r < 10^8.5L_⊙) blue sources indicate that they have, on average, more concentrated stellar mass distributions than the Nançay detections in the same luminosity range, suggesting we may be probing galaxies with intrinsically different properties. These follow-up observations enable us to probe Hi mass fractions, log(M_HI/M_⋆) 0.5 dex and 1 dex lower, on average, than the NIBLES and ALFALFA surveys respectively.