First Cosmology Results using Supernovae Ia from the Dark Energy Survey: Survey Overview, Performance, and Supernova Spectroscopy
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The ALMA-ALPINE [CII] survey is aimed at characterizing the properties of a sample of normal star-forming galaxies (SFGs). The ALMA Large Program to INvestigate (ALPINE) features 118 galaxies observed in the [CII]-158 μ m line and far infrared (FIR) continuum emission during the period of rapid mass assembly, right after the end of the HI reionization, at redshifts of 4 < z < 6. We present the survey science goals, the observational strategy, and the sample selection of the 118 galaxies observed with ALMA, with an average beam minor axis of about 0.85″, or ∼5 kpc at the median redshift of the survey. The properties of the sample are described, including spectroscopic redshifts derived from the UV-rest frame, stellar masses, and star-formation rates obtained from a spectral energy distribution (SED) fitting. The observed properties derived from the ALMA data are presented and discussed in terms of the overall detection rate in [CII] and FIR continuum, with the observed signal-to-noise distribution. The sample is representative of the SFG population in the main sequence at these redshifts. The overall detection rate in [CII] is 64% for a signal-to-noise ratio (S/N) threshold larger than 3.5 corresponding to a 95% purity (40% detection rate for S / N > 5). Based on a visual inspection of the [CII] data cubes together with the large wealth of ancillary data, we find a surprisingly wide range of galaxy types, including 40% that are mergers, 20% extended and dispersion-dominated, 13% compact, and 11% rotating discs, with the remaining 16% too faint to be classified. This diversity indicates that a wide array of physical processes must be at work at this epoch, first and foremost, those of galaxy mergers. This paper sets a reference sample for the gas distribution in normal SFGs at 4 < z < 6, a key epoch in galaxy assembly, which is ideally suited for studies with future facilities, such as the James Webb Space Telescope (JWST) and the Extremely Large Telescopes (ELTs).more » « less
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Context. Active galactic nuclei (AGN) are thought to be intimately connected with their host galaxies through feeding and feedback processes. A strong coupling is predicted and supported by cosmological simulations of galaxy formation, but the details of the physical mechanisms are still observationally unconstrained. Aims. Galaxies are complex systems of stars and a multiphase interstellar medium (ISM). A spatially resolved multiwavelength survey is required to map the interaction of AGN with their host galaxies on different spatial scales and different phases of the ISM. The goal of the Close AGN Reference Survey (CARS) is to obtain the necessary spatially resolved multiwavelength observations for an unbiased sample of local unobscured luminous AGN. Methods. We present the overall CARS survey design and the associated wide-field optical integral-field unit (IFU) spectroscopy for all 41 CARS targets at z < 0.06 randomly selected from the Hamburg/ESO survey of luminous unobscured AGN. This data set provides the backbone of the CARS survey and allows us to characterize host galaxy morphologies, AGN parameters, precise systemic redshifts, and ionized gas distributions including excitation conditions, kinematics, and metallicities in unprecedented detail. Results. We focus our study on the size of the extended narrow-line region (ENLR) which has been traditionally connected to AGN luminosity. Given the large scatter in the ENLR size–luminosity relation, we performed a large parameter search to identify potentially more fundamental relations. Remarkably, we identified the strongest correlation between the maximum projected ENLR size and the black hole mass, consistent with an R ENLR,max ∼ M BH 0.5 relationship. We interpret the maximum ENLR size as a timescale indicator of a single black hole (BH) radiative-efficient accretion episode for which we inferred 〈log( t AGN /[yr])〉 = (0.45 ± 0.08)log( M BH /[ M ⊙ ]) + 1.78 −0.67 +0.54 using forward modeling. The extrapolation of our inferred relation toward higher BH masses is consistent with an independent lifetime estimate from the He II proximity zones around luminous AGN at z ∼ 3. Conclusions. While our proposed link between the BH mass and AGN lifetime might be a secondary correlation itself or impacted by unknown biases, it has a few relevant implications if confirmed. For example, the famous AGN Eigenvector 1 parameter space may be partially explained by the range in AGN lifetimes. Also, the lack of observational evidence for negative AGN feedback on star formation can be explained by such timescale effects. Further observational tests are required to confirm or rule out our BH mass dependent AGN lifetime hypothesis.more » « less
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Abstract We describe the Perkins INfrared Exosatellite Survey (PINES), a near-infrared photometric search for short-period transiting planets and moons around a sample of 393 spectroscopically confirmed L- and T-type dwarfs. PINES is performed with Boston University’s 1.8 m Perkins Telescope Observatory, located on Anderson Mesa, Arizona. We discuss the observational strategy of the survey, which was designed to optimize the number of expected transit detections, and describe custom automated observing procedures for performing PINES observations. We detail the steps of the PINES Analysis Toolkit ( PAT ), software that is used to create light curves from PINES images. We assess the impact of second-order extinction due to changing precipitable water vapor on our observations and find that the magnitude of this effect is minimized in Mauna Kea Observatories J band. We demonstrate the validity of PAT through the recovery of a transit of WASP-2 b and known variable brown dwarfs, and use it to identify a new variable L/T transition object: the T2 dwarf WISE J045746.08-020719.2. We report on the measured photometric precision of the survey and use it to estimate our transit-detection sensitivity. We find that for our median brightness targets, assuming contributions from white noise only, we are sensitive to the detection of 2.5 R ⊕ planets and larger. PINES will test whether the increase in sub-Neptune-sized planet occurrence with decreasing host mass continues into the L- and T-dwarf regime.more » « less