Search Publications
Lens modelling of the strongly lensed Type Ia supernova iPTF16geu
Goldstein, D. A.; Amanullah, R.; Goobar, A. +3 more
In 2016, the first strongly lensed Type Ia supernova (SN Ia), iPTF16geu, at redshift z = 0.409 with four resolved images arranged symmetrically around the lens galaxy at z = 0.2163, was discovered. Here, refined observations of iPTF16geu, including the time delay between images, are used to decrease uncertainties in the lens model, including the t…
Progenitor, precursor, and evolution of the dusty remnant of the stellar merger M31-LRN-2015
Kozłowski, S.; Kochanek, C. S.; Johansson, J. +12 more
M31-LRN-2015 is a likely stellar merger discovered in the Andromeda Galaxy in 2015. We present new optical to mid-infrared photometry and optical spectroscopy for this event. Archival data show that the source started to brighten ~2 yr before the nova event. During this precursor phase, the source brightened by ~3 mag. The light curve at 6 and 1.5…
Magnesium abundances in cool metal-polluted white dwarfs
Blouin, Simon
The accretion of rocky material is responsible for the presence of heavy elements in the atmospheres of a large fraction of white dwarf stars. Those objects represent a unique opportunity to infer the bulk composition of exoplanetesimals. This chemical characterization requires the use of detailed atmosphere models to determine the elemental abund…
Fundamental effective temperature measurements for eclipsing binary stars - I. Development of the method and application to AI Phoenicis
Maxted, P. F. L.; Smalley, B.; Miller, N. J.
Stars with accurate and precise effective temperature (Teff) measurements are needed to test stellar atmosphere models and calibrate empirical methods to determine Teff. There are few standard stars currently available to calibrate temperature indicators for dwarf stars. Gaia parallaxes now make it possible, in principle, to …
The changing-type SN 2014C may come from an 11-M⊙ star stripped by binary interaction and violent eruption
Sun, Ning-Chen; Crowther, Paul A.; Maund, Justyn R.
SN 2014C was an unprecedented supernova (SN) that displayed a metamorphosis from Type Ib to Type IIn over ∼200 d. This transformation is consistent with a helium star having exploded in a cavity surrounded by a dense shell of the progenitor's stripped hydrogen envelope. For at least 5 yr post-explosion, the ejecta continued to interact with an out…
Lifetime of short-period binaries measured from their Galactic kinematics
Zakamska, Nadia L.; Hwang, Hsiang-Chih
As a significant fraction of stars are in multiple systems, binaries play a crucial role in stellar evolution. Among short-period (<1 d) binary characteristics, age remains one of the most difficult to measure. In this paper, we constrain the lifetime of short-period binaries through their kinematics. With the kinematic information from Gaia Da…
Probing the circumstellar medium 2.8 Gyr after the big bang: detection of Bowen fluorescence in the Sunburst arc
Castellano, M.; Grillo, C.; Brammer, G. B. +13 more
We discovered Bowen emission arising from a strongly lensed (i.e. with magnification factor µ > 20) source hosted in the Sunburst arc at z = 2.37. We claim this source is plausibly a transient stellar object and study the unique ultraviolet lines emerging from it. In particular, narrow (σv ≃ 40 km s-1) ionization lin…
Stellar parameter determination from photometry using invertible neural networks
Gennaro, Mario; Sabbi, Elena; Gouliermis, Dimitrios +7 more
Photometric surveys with the Hubble Space Telescope (HST) allow us to study stellar populations with high-resolution and deep coverage, with estimates of the physical parameters of the constituent stars being typically obtained by comparing the survey data with adequate stellar evolutionary models. This is a highly non-trivial task due to effects …
Cosmic evolution of star-forming galaxies to z ≃ 1.8 in the faint low-frequency radio source population
Prandoni, I.; Vaccari, M.; Mancuso, C. +4 more
We study the properties of star-forming galaxies selected at 610 MHz with the GMRT in a survey covering ∼1.86 deg2 down to a noise of ∼7.1 µJy beam-1. These were identified by combining multiple classification diagnostics: optical, X-ray, infrared, and radio data. Of the 1685 SFGs from the GMRT sample, 496 have spectros…
A large, deep 3 deg2 survey of H α, [O III], and [O II] emitters from LAGER: constraining luminosity functions
Hu, W.; Infante, L.; Walker, A. R. +14 more
We present our measurements of the H α, [O III], and [O II] luminosity functions as part of the Lyman Alpha Galaxies at Epoch of Reionization (LAGER) survey using our samples of 1577 z = 0.47 H α-, 3933 z = 0.93 [O III]-, and 5367 z = 1.59 [O II]-selected emission line galaxies in a 3 deg2 single, CTIO/Blanco DECam pointing of the COSMO…