J/ApJ/859/53 Ly{alpha} candidates from a MUSE survey of 6 AGNs (Marino+, 2018) ================================================================================ Dark galaxy candidates at redshift ~3.5 detected with MUSE. Marino R. A., Cantalupo S., Lilly S.J., Gallego S.G., Straka L.A., Borisova E., Pezzulli G., Bacon R., Brinchmann J., Carollo C.M., Caruana J., Conseil S., Contini T., Diener C., Finley H., Inami H., Leclercq F., Muzahid S., Richard J., Schaye J., Wendt M., Wisotzki L. =2018ApJ...859...53M ================================================================================ ADC_Keywords: Active gal. nuclei; QSOs; Redshifts; Spectra, optical Equivalent widths; Intergalactic medium; Surveys Keywords: galaxies: formation; galaxies: high-redshift; galaxies: star formation; intergalactic medium; quasars: emission lines; quasars: general Abstract: Recent theoretical models suggest that the early phase of galaxy formation could involve an epoch when galaxies are gas rich but inefficient at forming stars: a "dark galaxy" phase. Here, we report the results of our Multi-Unit Spectroscopic Explorer (MUSE) survey for dark galaxies fluorescently illuminated by quasars at z>3. Compared to previous studies which are based on deep narrowband (NB) imaging, our integral field survey provides a nearly uniform sensitivity coverage over a large volume in redshift space around the quasars as well as full spectral information at each location. Thanks to these unique features, we are able to build control samples at large redshift distances from the quasars using the same data taken under the same conditions. By comparing the rest-frame equivalent width (EW0) distributions of the Ly{alpha} sources detected in proximity to the quasars and in control samples, we detect a clear correlation between the locations of high-EW0 objects and the quasars. This correlation is not seen in other properties, such as Ly{alpha} luminosities or volume overdensities, suggesting the possible fluorescent nature of at least some of these objects. Among these, we find six sources without continuum counterparts and EW0 limits larger than 240{AA} that are the best candidates for dark galaxies in our survey at z>3.5. The volume densities and properties, including inferred gas masses and star formation efficiencies, of these dark galaxy candidates are similar to those of previously detected candidates at z~2.4 in NB surveys. Moreover, if the most distant of these are fluorescently illuminated by the quasar, our results also provide a lower limit of t=60Myr on the quasar lifetime. Description: Our observations were carried out with the Multi-Unit Spectroscopic Explorer (MUSE), the second-generation IFU mounted on the Very Large Telescope (VLT) at the Nasmyth B focus of the Yepun (Unit Telescope 4) in Paranal, Chile. MUSE has a uniquely powerful performance: a relatively large FoV (in wide-field mode, WFM, 1'x1') combined with the excellent spatial sampling (0.2") and spectral resolutions (R from ~1750 to ~3500) over a wide optical wavelength window (from 4650 to 9300{AA}) and high throughput (35% at 7500{AA}). The six medium-deep fields at z>3 analyzed in this study were observed between 2014 September and 2016 April. They form part of two MUSE Guaranteed Time Observation (GTO) programs (094.A-0396, 095.A-0708, 096.A-0345, 097.A-0251, 098.A-0678 PI: S. Lilly; 094.A-0131, 095.A-0200, 096.A-0222, 097.A-0089, 098.A-0216; PI: J. Schaye). File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file table1.dat 82 6 Major properties of the MUSE medium-deep fields table5.dat 63 175 Physical properties of the Ly{alpha} candidates -------------------------------------------------------------------------------- See also: VI/109 : Pop. Synthesis Models at very low metallicities (Schaerer, 2003) VII/260 : The SDSS-DR7 quasar catalog (Schneider+, 2010) VII/258 : Quasars and Active Galactic Nuclei (13th Ed.) (Veron+ 2010) J/A+A/392/395 : Ks-band magnitudes of the K20 sample (Cimatti+, 2002) J/ApJ/596/768 : Optical depths in 19 QSOs (Schaye+, 2003) J/A+A/523/A64 : UV properties of starbursts (Raiter+, 2010) J/A+A/548/A66 : SDSS Quasar Catalog, DR9Q (Paris+, 2012) J/ApJ/763/37 : Metals in SDSS QSOs. I. 1.5