@article{MarinoCantalupoLillyetal.2018,
  author    = {Marino, Raffaella Anna and Cantalupo, Sebastiano and Lilly, Simon J. and Gallego, Sofia G. and Straka, Lorrie A. and Borisova, Elena and Pezzulli, Gabriele and Bacon, Roland and Brinchmann, Jarle and Carollo, C. Marcella and Caruana, Joseph and Conseil, Simon and Contini, Thierry and Diener, Catrina and Finley, Hayley and Inami, Hanae and Leclercq, Floriane and Muzahid, Sowgat and Richard, Johan and Schaye, Joop and Wendt, Martin and Wisotzki, Lutz},
  title     = {Dark Galaxy Candidates at Redshift similar to 3.5 Detected with MUSE},
  series = {The astrophysical journal : an international review of spectroscopy and astronomical physics},
  volume    = {859},
  journal   = {The astrophysical journal : an international review of spectroscopy and astronomical physics},
  number    = {1},
  publisher = {IOP Publ. Ltd.},
  address   = {Bristol},
  issn      = {0004-637X},
  doi       = {10.3847/1538-4357/aab6aa},
  pages     = {22},
  year      = {2018},
  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 angstrom 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 approximate to 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 - 60 Myr on the quasar lifetime.},
  language  = {en}
}
@article{JohnsonChenStrakaetal.2018,
  author    = {Johnson, Sean D. and Chen, Hsiao-Wen and Straka, Lorrie and Schaye, Joop and Cantalupo, Sebastiano and Wendt, Martin and Muzahid, Sowgat and Bouch{\´e}, Nicolas and Herenz, Edmund Christian and Kollatschny, Wolfram and Mulchaey, John S. and Marino, Raffaella A. and Maseda, Michael and Wisotzki, Lutz},
  title     = {Galaxy and quasar fueling caught in the act from the intragroup to the interstellar medium},
  series = {The astrophysical journal : Part 2, Letters},
  volume    = {869},
  journal   = {The astrophysical journal : Part 2, Letters},
  number    = {1},
  publisher = {IOP Publishing Ltd. (Bristol)},
  address   = {Bristol},
  issn      = {2041-8205},
  doi       = {10.3847/2041-8213/aaf1cf},
  pages     = {7},
  year      = {2018},
  abstract  = {We report the discovery of six spatially extended (10-100 kpc) line-emitting nebulae in the z approximate to 0.57 galaxy group hosting PKS 0405-123, one of the most luminous quasars at z < 1. The discovery is enabled by the Multi Unit Spectroscopic Explorer and provides tantalizing evidence connecting large-scale gas streams with nuclear activity on scales of <10 proper kpc (pkpc). One of the nebulae exhibits a narrow, filamentary morphology extending over 50 pkpc toward the quasar with narrow internal velocity dispersion (50 km s(-1)) and is not associated with any detected galaxies, consistent with a cool intragroup medium filament. Two of the nebulae are 10 pkpc north and south of the quasar with tidal-arm-like morphologies. These two nebulae, along with a continuum-emitting arm extending 60 pkpc from the quasar, are signatures of interactions that are expected to redistribute angular momentum in the host interstellar medium (ISM) to facilitate star formation and quasar fueling in the nucleus. The three remaining nebulae are among the largest and most luminous [O III] emitting "blobs" known (1400-2400 pkpc(2)) and correspond both kinematically and morphologically to interacting galaxy pairs in the quasar host group, consistent with arising from stripped ISM rather than large-scale quasar outflows. The presence of these large- and small-scale nebulae in the vicinity of a luminous quasar bears significantly on the effect of large-scale environment on galaxy and black hole fueling, providing a natural explanation for the previously known correlation between quasar luminosity and cool circumgalactic medium.},
  language  = {en}
}
@article{SchmidtHennawiWorsecketal.2018,
  author    = {Schmidt, Tobias M. and Hennawi, Joseph F. and Worseck, Gabor and Davies, Frederick B. and Lukic, Zarija and O{\~n}orbe, Jose},
  title     = {Modeling the HeII transverse proximity effect},
  series = {The astrophysical journal : an international review of spectroscopy and astronomical physics},
  volume    = {861},
  journal   = {The astrophysical journal : an international review of spectroscopy and astronomical physics},
  number    = {2},
  publisher = {IOP Publ. Ltd.},
  address   = {Bristol},
  issn      = {0004-637X},
  doi       = {10.3847/1538-4357/aac8e4},
  pages     = {20},
  year      = {2018},
  abstract  = {The He II transverse proximity effect-enhanced He II Ly alpha transmission in a background sightline caused by the ionizing radiation of a foreground quasar-offers a unique opportunity to probe the emission properties of quasars, in particular the emission geometry (obscuration, beaming) and the quasar lifetime. Building on the foreground quasar survey published in Schmidt et al., we present a detailed model of the He II transverse proximity effect, specifically designed to include light travel time effects, finite quasar ages, and quasar obscuration. We postprocess outputs from a cosmological hydrodynamical simulation with a fluctuating He II ultraviolet background model, with the added effect of the radiation from a single bright foreground quasar. We vary the age t(age) and obscured sky fractions Omega(obsc) of the foreground quasar, and explore the resulting effect on the He II transverse proximity effect signal. Fluctuations in intergalactic medium density and the ultraviolet background, as well as the unknown orientation of the foreground quasar, result in a large variance of the He II Ly alpha transmission along the background sightline. We develop a fully Bayesian statistical formalism to compare far-ultraviolet He II Ly alpha transmission spectra of the background quasars to our models, and extract joint constraints on t(age) and Omega(obsc) for the six Schmidt et al. foreground quasars with the highest implied He II photoionization rates. Our analysis suggests a bimodal distribution of quasar emission properties, whereby one foreground quasar, associated with a strong He II transmission spike, is relatively old (22 Myr) and unobscured (Omega(obsc) < 35\%), whereas three others are either younger than 10 Myr or highly obscured (Omega(obsc) > 70\%).},
  language  = {en}
}
@article{AbeysekaraArcherBenbowetal.2018,
  author    = {Abeysekara, A. U. and Archer, A. and Benbow, Wystan and Bird, Ralph and Brill, A. and Brose, Robert and Buckley, J. H. and Christiansen, Jessie L. and Chromey, A. J. and Daniel, M. K. and Falcone, A. and Feng, Qi and Finley, John P. and Fortson, L. and Furniss, Amy and Gillanders, Gerard H. and Gueta, O. and Hanna, David and Hervet, O. and Holder, J. and Hughes, G. and Humensky, T. B. and Johnson, Caitlin A. and Kaaret, Philip and Kar, P. and Kelley-Hoskins, N. and Kertzman, M. and Kieda, David and Krause, Maria and Krennrich, F. and Lang, M. J. and Moriarty, P. and Mukherjee, Reshmi and Ong, R. A. and Otte, A. N. and Park, N. and Petrashyk, A. and Pohl, Martin and Pueschel, Elisa and Quinn, J. and Ragan, K. and Reynolds, P. T. and Richards, Gregory T. and Roache, E. and Rulten, C. and Sadeh, I. and Santander, Marcos and Scott, S. S. and Sembroski, G. H. and Shahinyan, Karlen and Tyler, J. and Wakely, S. P. and Weinstein, A. and Wells, R. M. and Wilcox, P. and Wilhelm, Alina and Williams, D. A. and Williamson, T. J. and Zitzer, B. and Kaur, A.},
  title     = {VERITAS Observations of the BL Lac Object TXS 0506+056},
  series = {The astrophysical journal : an international review of spectroscopy and astronomical physics ; Part 2, Letters},
  volume    = {861},
  journal   = {The astrophysical journal : an international review of spectroscopy and astronomical physics ; Part 2, Letters},
  number    = {2},
  publisher = {IOP Publ. Ltd.},
  address   = {Bristol},
  organization    = {VERITAS Collaboration},
  issn      = {2041-8205},
  doi       = {10.3847/2041-8213/aad053},
  pages     = {6},
  year      = {2018},
  abstract  = {On 2017 September 22, the IceCube Neutrino Observatory reported the detection of the high-energy neutrino event IC 170922A, of potential astrophysical origin. It was soon determined that the neutrino direction was consistent with the location of the gamma-ray blazar TXS 0506+056. (3FGL J0509.4+ 0541), which was in an elevated gamma-ray emission state as measured by the Fermi satellite. Very Energetic Radiation Imaging Telescope Array System (VERITAS) observations of the neutrino/blazar region started on 2017 September 23 in response to the neutrino alert and continued through 2018 February 6. While no significant very-high-energy (VHE; E > 100 GeV) emission was observed from the blazar by VERITAS in the two-week period immediately following the IceCube alert, TXS 0506+ 056 was detected by VERITAS with a significance of 5.8 standard deviations (sigma) in the full 35 hr data set. The average photon flux of the source during this period was (8.9 +/- 1.6). x. 10(-12) cm(-2) s(-1), or 1.6\% of the Crab Nebula flux, above an energy threshold of 110 GeV, with a soft spectral index of 4.8. +/-. 1.3.},
  language  = {en}
}