Eddington-Limited Accretion in z~2 WISE-selected Hot, Dust-Obscured Galaxies

Hot, Dust-Obscured Galaxies, or "Hot DOGs", are a rare, dusty, hyperluminous galaxy population discovered by the WISE mission. Predominantly at redshifts 2-3, they include the most luminous known galaxies in the universe. Their high luminosities likely come from accretion onto highly obscured super massive black holes (SMBHs). We have conducted a pilot survey to measure the SMBH masses of five z~2 Hot DOGs via broad H_alpha emission lines, using Keck/MOSFIRE and Gemini/FLAMINGOS-2. We detect broad H_alpha emission in all five Hot DOGs. We find substantial corresponding SMBH masses for these Hot DOGs (~ 10^{9} M_sun), and their derived Eddington ratios are close to unity. These z~2 Hot DOGs are the most luminous AGNs at given BH masses, suggesting they are accreting at the maximum rates for their BHs. A similar property is found for known z~6 quasars. Our results are consistent with scenarios in which Hot DOGs represent a transitional, high-accretion phase between obscured and unobscured quasars. Hot DOGs may mark a special evolutionary stage before the red quasar and optical quasar phases, and they may be present at other cosmic epochs.Comment: 15 pages, 9 figures. Accepted by Ap

The Massive and Distant Clusters of WISE Survey: MOO J1142+1527, a 10^(15) M_⊙ Galaxy Cluster at z = 1.19

We present confirmation of the cluster MOO J1142+1527, a massive galaxy cluster discovered as part of the Massive and Distant Clusters of WISE Survey. The cluster is confirmed to lie at z = 1.19, and using the Combined Array for Research in Millimeter-wave Astronomy we robustly detect the Sunyaev–Zel'dovich (SZ) decrement at 13.2σ. The SZ data imply a mass of M_(200m) = (1.1 ± 0.2) × 10^(15)M_⊙, making MOO J1142+1527 the most massive galaxy cluster known at z > 1.15 and the second most massive cluster known at z > 1. For a standard ΛCDM cosmology it is further expected to be one of the ~5 most massive clusters expected to exist at z ≥ 1.19 over the entire sky. Our ongoing Spitzer program targeting ~1750 additional candidate clusters will identify comparably rich galaxy clusters over the full extragalactic sky

Addressing Challenges on the Dark Energy Spectroscopic Instrument (DESI)

The Dark Energy Spectroscopic Instrument (DESI) is under construction to measure the expansion history of the universe using the baryon acoustic oscillations technique. The spec- tra of 35 million galaxies and quasars over 14,000 square degrees will be measured during a 5-year survey. A new prime focus corrector for the Mayall telescope at Kitt Peak National Observatory will deliver light to 5,000 individually targeted fiber-fed robotic positioners. The fibers in turn feed ten broadband multi-object spectrographs. This thesis details origi- nal work done in support of the DESI experiment, both for the instrument and survey design and optimization. First, I describe a novel approach for connecting optical fibers using fusion splicing, a method that will be implemented on DESI. Then, I will describe the ProtoDESI experiment, an on-sky technology demonstration with the goal to reduce technical risks asso- ciated with aligning optical fibers with targets using robotic fiber positioners and maintaining the stability required to operate DESI. The ProtoDESI prime focus instrument, which was installed and commissioned on the 4-m Mayall telescope from 2016 August 14 to September 30, consisted of three fiber positioners, illuminated fiducials, and a guide camera. ProtoDESI was successful in acquiring targets with the robotically positioned fibers and demonstrated that the DESI guiding requirements can be met. Finally, I will describe a predictive sky background model for DESI, which is built on the spectra from the 5-year Baryon Oscilla- tion Spectroscopic Survey (BOSS). This dataset consists of ∼1 million unique sky spectra covering 360 - 1040 nm collected in a variety of observational conditions. We measure an inter-airglow line continuum value of ∼ 0.81×10−17erg/cm2/s/ ̊A/arcsec2 in dark time across the full wavelength range, with a variance of ∼ 0.175 × 10−17erg/cm2/s/ ̊A/arcsec2. The de- tailed model, which accounts for 50% of the variance, shows that the dark sky continuum consists of ∼ 30% zodiacal light and is significantly impacted by solar activity. The improved spectroscopic sky background model can be used in simulations and forecasting for DESI and other surveys

Addressing Challenges on the Dark Energy Spectroscopic Instrument (DESI)

The Dark Energy Spectroscopic Instrument (DESI) is under construction to measure the expansion history of the universe using the baryon acoustic oscillations technique. The spec- tra of 35 million galaxies and quasars over 14,000 square degrees will be measured during a 5-year survey. A new prime focus corrector for the Mayall telescope at Kitt Peak National Observatory will deliver light to 5,000 individually targeted fiber-fed robotic positioners. The fibers in turn feed ten broadband multi-object spectrographs. This thesis details origi- nal work done in support of the DESI experiment, both for the instrument and survey design and optimization. First, I describe a novel approach for connecting optical fibers using fusion splicing, a method that will be implemented on DESI. Then, I will describe the ProtoDESI experiment, an on-sky technology demonstration with the goal to reduce technical risks asso- ciated with aligning optical fibers with targets using robotic fiber positioners and maintaining the stability required to operate DESI. The ProtoDESI prime focus instrument, which was installed and commissioned on the 4-m Mayall telescope from 2016 August 14 to September 30, consisted of three fiber positioners, illuminated fiducials, and a guide camera. ProtoDESI was successful in acquiring targets with the robotically positioned fibers and demonstrated that the DESI guiding requirements can be met. Finally, I will describe a predictive sky background model for DESI, which is built on the spectra from the 5-year Baryon Oscilla- tion Spectroscopic Survey (BOSS). This dataset consists of ∼1 million unique sky spectra covering 360 - 1040 nm collected in a variety of observational conditions. We measure an inter-airglow line continuum value of ∼ 0.81×10−17erg/cm2/s/ ̊A/arcsec2 in dark time across the full wavelength range, with a variance of ∼ 0.175 × 10−17erg/cm2/s/ ̊A/arcsec2. The de- tailed model, which accounts for 50% of the variance, shows that the dark sky continuum consists of ∼ 30% zodiacal light and is significantly impacted by solar activity. The improved spectroscopic sky background model can be used in simulations and forecasting for DESI and other surveys

See Change: the Supernova Sample from the Supernova Cosmology Project High Redshift Cluster Supernova Survey

Brian Hayden et al. -- The 229th Amerian Astronomical Society Meeting, Grapevine, Texas, 3-7 January 2017The Supernova Cosmology Project has finished executing a large (174 orbits, cycles 22-23) Hubble Space Telescope program, which has measured ~30 type Ia Supernovae above z~1 in the highest-redshift, most massive galaxy clusters known to date. Our SN Ia sample closely matches our pre-survey predictions; this sample will improve the constraint by a factor of 3 on the Dark Energy equation of state above z~1, allowing an unprecedented probe of Dark Energy time variation. When combined with the improved cluster mass calibration from gravitational lensing provided by the deep WFC3-IR observations of the clusters, See Change will triple the Dark Energy Task Force Figure of Merit. With the primary observing campaign completed, we present the preliminary supernova sample and our path forward to the supernova cosmology results. We also compare the number of SNe Ia discovered in each cluster with our pre-survey expectations based on cluster mass and SFR estimates. Our extensive HST and ground-based campaign has already produced unique results; we have confirmed several of the highest redshift cluster members known to date, confirmed the redshift of one of the most massive galaxy clusters at z~1.2 expected across the entire sky, and characterized one of the most extreme starburst environments yet known in a z~1.7 cluster. We have also discovered a lensed SN Ia at z=2.22 magnified by a factor of ~2.7, which is the highest spectroscopic redshift SN Ia currently known.Peer Reviewe

See Change: the Supernova Sample from the Supernova Cosmology Project High Redshift Cluster Supernova Survey

Brian Hayden et al. -- The 229th Amerian Astronomical Society Meeting, Grapevine, Texas, 3-7 January 2017The Supernova Cosmology Project has finished executing a large (174 orbits, cycles 22-23) Hubble Space Telescope program, which has measured ~30 type Ia Supernovae above z~1 in the highest-redshift, most massive galaxy clusters known to date. Our SN Ia sample closely matches our pre-survey predictions; this sample will improve the constraint by a factor of 3 on the Dark Energy equation of state above z~1, allowing an unprecedented probe of Dark Energy time variation. When combined with the improved cluster mass calibration from gravitational lensing provided by the deep WFC3-IR observations of the clusters, See Change will triple the Dark Energy Task Force Figure of Merit. With the primary observing campaign completed, we present the preliminary supernova sample and our path forward to the supernova cosmology results. We also compare the number of SNe Ia discovered in each cluster with our pre-survey expectations based on cluster mass and SFR estimates. Our extensive HST and ground-based campaign has already produced unique results; we have confirmed several of the highest redshift cluster members known to date, confirmed the redshift of one of the most massive galaxy clusters at z~1.2 expected across the entire sky, and characterized one of the most extreme starburst environments yet known in a z~1.7 cluster. We have also discovered a lensed SN Ia at z=2.22 magnified by a factor of ~2.7, which is the highest spectroscopic redshift SN Ia currently known.Peer Reviewe

Performance of the Dark Energy Spectroscopic Instrument (DESI) focal plane

International audienceThe recently commissioned Dark Energy Spectroscopic Instrument (DESI) will measure the expansion history of the Universe using the Baryon Acoustic Oscillation technique. The spectra of 35 million galaxies and quasars over 14,000 sq deg will be measured during the life of the experiment. A new prime focus corrector for the KPNO Mayall telescope delivers light to 5,000 fiber optic positioners which in turn feed ten broad-band spectro- graphs. The DESI focal plane subsystem contains the fiber optic positioners and guide and focus cameras, which enable the alignment of fibers with astronomical targets. This paper describes the performance of the installed instrument