Search Publications
The first measurement of the quasar lifetime distribution
Hennawi, Joseph F.; Worseck, Gábor; Davies, Frederick B. +1 more
Understanding the growth of the supermassive black holes (SMBH) powering luminous quasars, their co-evolution with host galaxies, and impact on the surrounding intergalactic medium (IGM) depends sensitively on the duration of quasar accretion episodes. Unfortunately, this time-scale, known as the quasar lifetime, tQ, is still uncertain …
The relativistic jet dichotomy and the end of the blazar sequence
Georganopoulos, Markos; Meyer, Eileen T.; Reddy, Karthik +2 more
Our understanding of the unification of jetted AGN has evolved greatly as jet samples have increased in size. Here, based on the largest-ever sample of over 2000 well-sampled jet spectral energy distributions, we examine the synchrotron peak frequency - peak luminosity plane, and find little evidence for the anticorrelation known as the blazar seq…
Star cluster classification in the PHANGS-HST survey: Comparison between human and machine learning approaches
Van Dyk, Schuyler D.; Kruijssen, J. M. Diederik; Rosolowsky, Erik +21 more
When completed, the PHANGS-HST project will provide a census of roughly 50 000 compact star clusters and associations, as well as human morphological classifications for roughly 20 000 of those objects. These large numbers motivated the development of a more objective and repeatable method to help perform source classifications. In this paper, we …
Cepheid metallicity in the Leavitt law (C-metall) survey - I. HARPS-N@TNG spectroscopy of 47 classical Cepheids and 1 BL Her variables
Clementini, G.; Ripepi, V.; Molinaro, R. +11 more
Classical Cepheids (DCEPs) are the most important primary indicators of the extragalactic distance scale. Establishing the dependence on metallicity of their period-luminosity and period-Wesenheit (PLZ/PWZ) relations has deep consequences on the calibration of secondary distance indicators that lead to the final estimate of the Hubble constant (H<…
Powerful winds in high-redshift obscured and red quasars
Hamann, Fred; Veilleux, Sylvain; Zakamska, Nadia L. +10 more
Quasar-driven outflows must have made their most significant impact on galaxy formation during the epoch when massive galaxies were forming most rapidly. To study the impact of quasar feedback, we conducted rest-frame optical integral field spectrograph (IFS) observations of three extremely red quasars (ERQs) and one type-2 quasar at z = 2-3, obta…
The nucleation fraction of local volume galaxies
Neumayer, Nadine; Greene, Jenny E.; Seth, Anil C. +2 more
Nuclear star clusters (NSCs) are a common phenomenon in galaxy centres and are found in a vast majority of galaxies of intermediate stellar mass $\approx 10^9\, \mathrm{M}_{\odot }$. Recent investigations suggest that they are rarely found in the least and most massive galaxies and that the nucleation fraction increases in dense environments. It i…
The most massive white dwarfs in the solar neighbourhood
Bergeron, P.; Blouin, Simon; Kilic, Mukremin +1 more
We present an analysis of the most massive white dwarf candidates in the Montreal White Dwarf Database 100 pc sample. We identify 25 objects that would be more massive than $1.3\, {\rm M}_{\odot }$ if they had pure H atmospheres and CO cores, including two outliers with unusually high photometric mass estimates near the Chandrasekhar limit. We pro…
The MOSDEF survey: a comprehensive analysis of the rest-optical emission-line properties of z ∼ 2.3 star-forming galaxies
Barro, Guillermo; Siana, Brian; Shapley, Alice E. +16 more
We analyse the rest-optical emission-line spectra of z ~ 2.3 star-forming galaxies in the complete MOSFIRE Deep Evolution Field (MOSDEF) survey. In investigating the origin of the well-known offset between the sequences of high-redshift and local galaxies in the [O III]λ5008/Hβ versus [N II]λ6585/Hα ('[N II] BPT') diagram, we define two population…
TESS survey of rotational and pulsational variability of mercury-manganese stars
Neiner, C.; Paunzen, E.; Kochukhov, O. +4 more
Mercury-manganese (HgMn) stars are late-B upper main sequence chemically peculiar stars distinguished by large overabundances of heavy elements, slow rotation, and frequent membership in close binary systems. These stars lack strong magnetic fields typical of magnetic Bp stars but occasionally exhibit non-uniform surface distributions of chemical …
The GOGREEN and GCLASS surveys: first data release
Cooper, M. C.; Matharu, Jasleen; Muzzin, Adam +43 more
We present the first public data release of the GOGREEN (Gemini Observations of Galaxies in Rich Early Environments) and GCLASS (Gemini CLuster Astrophysics Spectroscopic Survey) surveys of galaxies in dense environments, spanning a redshift range 0.8 < z < 1.5. The surveys consist of deep, multiwavelength photometry and extensive Gemini GMO…