Search Publications
Galaxy Zoo: quantitative visual morphological classifications for 48 000 galaxies from CANDELS
Finkelstein, Steven L.; Barro, Guillermo; Bell, Eric F. +46 more
We present quantified visual morphologies of approximately 48 000 galaxies observed in three Hubble Space Telescope legacy fields by the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) and classified by participants in the Galaxy Zoo project. 90 per cent of galaxies have z ≤ 3 and are observed in rest-frame optical wavelen…
The MOSDEF Survey: AGN Multi-wavelength Identification, Selection Biases, and Host Galaxy Properties
Siana, Brian; Azadi, Mojegan; Aird, James +10 more
We present results from the MOSFIRE Deep Evolution Field (MOSDEF) survey on the identification, selection biases, and host galaxy properties of 55 X-ray, IR, and optically selected active galactic nuclei (AGNs) at 1.4< z< 3.8. We obtain rest-frame optical spectra of galaxies and AGNs and use the BPT diagram to identify optical AGNs. We exami…
SPIRITS: Uncovering Unusual Infrared Transients with Spitzer
Van Dyk, Schuyler D.; Tinyanont, Samaporn; Smith, Nathan +44 more
We present an ongoing, five-year systematic search for extragalactic infrared transients, dubbed SPIRITS—SPitzer InfraRed Intensive Transients Survey. In the first year, using Spitzer/IRAC, we searched 190 nearby galaxies with cadence baselines of one month and six months. We discovered over 1958 variables and 43 transients. Here, we describe the …
Mapping substructure in the HST Frontier Fields cluster lenses and in cosmological simulations
Richard, Johan; Vogelsberger, Mark; Pillepich, Annalisa +14 more
We map the lensing-inferred substructure in the first three clusters observed by the Hubble Space Telescope Frontier Fields (HSTFF) Initiative: Abell 2744 (z = 0.308), MACSJ 0416, (z = 0.396) and MACSJ 1149 (z = 0.543). Statistically resolving dark matter subhaloes down to ∼10^{9.5} M_{⊙}, we compare the derived subhalo mass functions (SHMFs) to t…
VLBI-Gaia offsets favor parsec-scale jet direction in active galactic nuclei
Petrov, L.; Kovalev, Y. Y.; Plavin, A. V.
Context. The data release 1 (DR1) of milliarcsecond-scale accurate optical positions of stars and galaxies was recently published by the space mission Gaia.
Aims: We study the offsets of highly accurate absolute radio (very long baseline interferometry, VLBI) and optical positions of active galactic nuclei (AGN) to see whether or not a signat…
Living on a Flare: Relativistic Reflection in V404 Cyg Observed by NuSTAR during Its Summer 2015 Outburst
Harrison, F. A.; Stern, D.; Fabian, A. C. +19 more
We present first results from a series of NuSTAR observations of the black hole X-ray binary V404 Cyg obtained during its summer 2015 outburst, primarily focusing on observations during the height of this outburst activity. The NuSTAR data show extreme variability in both the flux and spectral properties of the source. This is partly driven by str…
A merger in the dusty, z = 7.5 galaxy A1689-zD1?
Richard, Johan; Gallazzi, Anna; Knudsen, Kirsten K. +5 more
The gravitationally lensed galaxy A1689-zD1 is one of the most distant spectroscopically confirmed sources (z = 7.5). It is the earliest known galaxy where the interstellar medium (ISM) has been detected; dust emission was detected with the Atacama Large Millimetre Array (ALMA). A1689-zD1 is also unusual among high-redshift dust emitters as it is …
NGC 6819: testing the asteroseismic mass scale, mass loss and evidence for products of non-standard evolution
Chaplin, W. J.; Handberg, R.; Bossini, D. +5 more
We present an extensive peakbagging effort on Kepler data of ∼50 red giant stars in the open star cluster NGC 6819. By employing sophisticated pre-processing of the time series and Markov chain Monte Carlo techniques we extracted individual frequencies, heights and line widths for hundreds of oscillation modes. We show that the 'average' asterosei…
Relativistic deflection of background starlight measures the mass of a nearby white dwarf star
Brown, Thomas M.; Casertano, Stefano; Anderson, Jay +12 more
Gravitational deflection of starlight around the Sun during the 1919 total solar eclipse provided measurements that confirmed Einstein’s general theory of relativity. We have used the Hubble Space Telescope to measure the analogous process of astrometric microlensing caused by a nearby star, the white dwarf Stein 2051 B. As Stein 2051 B passed clo…
Protostellar and cometary detections of organohalogens
Bourke, Tyler L.; Rosina Team; Öberg, Karin I. +15 more
Organohalogens, a class of molecules that contain at least one halogen atom bonded to carbon, are abundant on the Earth where they are mainly produced through industrial and biological processes1. Consequently, they have been proposed as biomarkers in the search for life on exoplanets2. Simple halogen hydrides have been detec…