Search Publications
The evolution of rest-frame UV properties, Ly α EWs, and the SFR-stellar mass relation at z ∼ 2-6 for SC4K LAEs
da Cunha, E.; Arrabal Haro, P.; Sobral, D. +6 more
We explore deep rest-frame UV to FIR data in the COSMOS field to measure the individual spectral energy distributions (SED) of the ∼4000 SC4K (Sobral et al.) Lyman α (Ly α) emitters (LAEs) at z ∼ 2-6. We find typical stellar masses of 109.3 ± 0.6 M⊙ and star formation rates (SFR) of SFR_SED=4.4^{+10.5}_{-2.4} M⊙ yr…
Superflares and variability in solar-type stars with TESS in the Southern hemisphere
Doyle, J. G.; Ramsay, G.; Doyle, L.
Superflares on solar-type stars have been a rapidly developing field ever since the launch of Kepler. Over the years, there have been several studies investigating the statistics of these explosive events. In this study, we present a statistical analysis of stellar flares on solar-type stars made using photometric data in 2-min cadence from Transi…
Multiple chemodynamic stellar populations of the Ursa Minor dwarf spheroidal galaxy
Djorgovski, S. G.; Geha, Marla; Simon, Joshua D. +6 more
We present a Bayesian method to identify multiple (chemodynamic) stellar populations in dwarf spheroidal galaxies (dSphs) using velocity, metallicity, and positional stellar data without the assumption of spherical symmetry. We apply this method to a new Keck/Deep Imaging Multi-Object Spectrograph (DEIMOS) spectroscopic survey of the Ursa Minor (U…
The growth of brightest cluster galaxies and intracluster light over the past 10 billion years
Donahue, Megan; Mulchaey, John S.; Connor, Thomas +9 more
We constrain the evolution of the brightest cluster galaxy plus intracluster light (BCG + ICL) using an ensemble of 42 galaxy groups and clusters that span redshifts of z = 0.05-1.75 and masses of M500,c= 2 × 1013-1015 M⊙. Specifically, we measure the relationship between the BCG + ICL stellar mass M
Candidate Population III stellar complex at z = 6.629 in the MUSE Deep Lensed Field
Treu, T.; Castellano, M.; Pentericci, L. +20 more
We discovered a strongly lensed (µ ≳ 40) Ly α emission at z = 6.629 (S/N ≃ 18) in the MUSE Deep Lensed Field (MDLF) targeting the Hubble Frontier Field (HFF) galaxy cluster MACS J0416. Dedicated lensing simulations imply that the Ly α emitting region necessarily crosses the caustic. The arc-like shape of the Ly α extends 3 arcsec on the obse…
Age demographics of the Milky Way disc and bulge
Evans, N. W.; Belokurov, V.; Grady, J.
We exploit the extensive Gaia Data Release 2 set of long-period variables to select a sample of O-rich Miras throughout the Milky Way disc and bulge for study. Exploiting the relation between Mira pulsation period and stellar age/chemistry, we slice the stellar density of the Galactic disc and bulge as a function of period. We find that the morpho…
The Tidal Disruption Event AT 2018hyz II: Light-curve modelling of a partially disrupted star
Eftekhari, Tarraneh; Berger, Edo; Chornock, Ryan +18 more
AT 2018hyz (= ASASSN-18zj) is a tidal disruption event (TDE) located in the nucleus of a quiescent E+A galaxy at a redshift of z = 0.04573, first detected by the All-Sky Automated Survey for Supernovae (ASAS-SN). We present optical+UV photometry of the transient, as well as an X-ray spectrum and radio upper limits. The bolometric light curve of AT…
A closer look at the spur, blob, wiggle, and gaps in GD-1
Gieles, M.; Erkal, D.; de Boer, T. J. L.
The GD-1 stream is one of the longest and coldest stellar streams discovered to date, and one of the best objects for constraining the dark matter properties of the Milky Way. Using data from Gaia DR2, we study the proper motions (PMs), distance, morphology, and density of the stream to uncover small-scale perturbations. The PM cleaned data show a…
The unusual broad-band X-ray spectral variability of NGC 1313 X-1 seen with XMM-Newton, Chandra, and NuSTAR
Harrison, F. A.; Stern, D.; Fabian, A. C. +19 more
We present results from the major coordinated X-ray observing programme on the ULX NGC 1313 X-1 performed in 2017, combining XMM-Newton, Chandra, and NuSTAR, focusing on the evolution of the broad-band (∼0.3-30.0 keV) continuum emission. Clear and unusual spectral variability is observed, but this is markedly suppressed above ∼10-15 keV, qualitati…
Searching for ultra-fast outflows in AGN using variability spectra
Schartel, N.; Santos-Lleó, M.; Buisson, D. J. K. +9 more
We present a qualitative search for ultra-fast outflows (UFOs) in excess variance spectra of radio-quiet active galactic nuclei (AGNs). We analyse 42 sources from the spectroscopic UFO detection sample, and an additional 22 different sources from the variability sample. A total of 58 sources have sufficient observational data from XMM-Newton EPIC-…