Census of the Local Universe (CLU) Narrowband Survey. I. Galaxy Catalogs from Preliminary Fields

Abstract

We present the Census of the Local Universe (CLU) narrow-band survey to search for emission-line (Hα) galaxies. CLU-Hα has imaged ≈3π of the sky (26,470 deg 2 ) with 4 narrow-band filters that probe a distance out to 200 Mpc. We have obtained spectroscopic follow-up for galaxy candidates in 14 preliminary fields (101.6 deg 2 ) to characterize the limits and completeness of the survey. In these preliminary fields, CLU can identify emission lines down to an Hα flux limit of 10 −14 erg s −1 cm −2 at 90% completeness, and recovers 83% (67%) of the Hα flux from catalogued galaxies in our search volume at the Σ=2.5 (Σ=5) color excess levels. The contamination from galaxies with no emission lines is 61% (12%) for Σ=2.5 (Σ=5). Also, in the regions of overlap between our preliminary fields and previous emission-line surveys, we recover the majority of the galaxies found in previous surveys and identify an additional ≈300 galaxies. In total, we find 90 galaxies with no previous distance information, several of which are interesting objects: 7 blue compact dwarfs, 1 green pea, and a Seyfert galaxy; we also identified a known planetary nebula. These objects show that the CLU-Hα survey can be a discovery machine for objects in our own Galaxy and extreme galaxies out to intermediate redshifts. However, the majority of the CLU-Hα galaxies identified in this work show properties consistent with normal star-forming galaxies. CLU-Hα galaxies with new redshifts will be added to existing galaxy catalogs to focus the search for the electromagnetic counterpart to gravitational wave events.

GROWTH on S190425z: Searching Thousands of Square Degrees to Identify an Optical or Infrared Counterpart to a Binary Neutron Star Merger with the Zwicky Transient Facility and Palomar Gattini-IR

“…This strategy was used by a number of teams to observe GW170817 (Arcavi et al 2017b;Coulter et al 2017;Valenti et al 2017). The galaxy-targeted follow-up program relies on the Census of the Local Universe catalog (Cook et al 2019); it is complete to 85% in star formation and 70% in stellar mass at 200 Mpc. The sky area coverage of galaxies is ≈1% within these local volumes (Cook et al 2019).…”

“…The galaxy-targeted follow-up program relies on the Census of the Local Universe catalog (Cook et al 2019); it is complete to 85% in star formation and 70% in stellar mass at 200 Mpc. The sky area coverage of galaxies is ≈1% within these local volumes (Cook et al 2019). This makes targeted galaxy pointing tractable for small FOV telescopes (see Arcavi et al 2017a or Golkhou et al 2018 for example).…”

Optimizing gravitational waves follow-up using galaxies stellar mass

“…The current binary neutron star range is at 130 Mpc for LIGO Livingston, 110 Mpc for LIGO Hanford, and 50 Mpc for Virgo (Abbott et al 2018a). The CLU catalog (Cook et al 2019) for the north hemisphere contains the WISE1 luminosity information as well as spectroscopic measurement of local galaxies, however it is non publicly available. Therefore, for the purpose of our work, we rely on the publicly available GLADE galaxy catalog (Dálya et al 2018) which is all-sky and complete up to 100Mpc, and nearly complete up to 150Mpc.…”

The H.E.S.S. gravitational wave rapid follow-up program

“…In order to use the cross-correlation introduced in the previous section, two catalogs of galaxies have been considered: The Census of the Local Universe (CLU) catalog [23] and The Galaxy List for the Advanced Detector Era (GLADE) catalog [24]. The latter is currently being used in the H.E.S.S.…”