Search Publications
The Systematic Properties of the Warm Phase of Starburst-Driven Galactic Winds
Heckman, Timothy M.; Leitherer, Claus; Borthakur, Sanchayeeta +2 more
Using ultraviolet absorption lines, we analyze the systematic properties of the warm ionized phase of starburst-driven winds in a sample of 39 low-redshift objects that spans broad ranges in starburst and galaxy properties. Total column densities for the outflows are ∼1021 cm-2. The outflow velocity (vout) correlat…
The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters - V. Constraints on formation scenarios
Dalessandro, E.; Salaris, M.; Anderson, J. +16 more
We build on the evidence provided by our Legacy Survey of Galactic globular clusters (GC) to submit to a crucial test four scenarios currently entertained for the formation of multiple stellar generations in GCs. The observational constraints on multiple generations to be fulfilled are manifold, including GC specificity, ubiquity, variety, predomi…
Properties of AGN coronae in the NuSTAR era
Fabian, A. C.; Reynolds, C. S.; Lohfink, A. +3 more
The focusing optics of NuSTAR have enabled high signal-to-noise ratio spectra to be obtained from many X-ray bright active galactic nuclei (AGN) and galactic black hole binaries (BHB). Spectral modelling then allows robust characterization of the spectral index and upper energy cutoff of the coronal power-law continuum, after accounting for reflec…
Forming Compact Massive Galaxies
van Dokkum, Pieter G.; Franx, Marijn; Illingworth, Garth D. +13 more
In this paper we study a key phase in the formation of massive galaxies: the transition of star-forming galaxies into massive (Mstars ∼ 1011M⊙), compact (re ∼ 1 kpc) quiescent galaxies, which takes place from z ∼ 3 to z ∼ 1.5. We use HST grism redshifts and extensive photometry in all five 3D-HST/CANDELS…
Inventory of the volatiles on comet 67P/Churyumov-Gerasimenko from Rosetta/ROSINA
De Keyser, Johan; Gombosi, Tamas I.; Berthelier, Jean-Jacques +15 more
Context. The ESA Rosetta spacecraft (S/C) is tracking comet 67P/Churyumov-Gerasimenko in close vicinity. This prolonged encounter enables studying the evolution of the volatile coma composition.
Aims: Our work aims at comparing the diversity of the coma of 67P/Churyumov-Gerasimenko at large heliocentric distance to study the evolution of the …
Evidence for PopIII-like Stellar Populations in the Most Luminous Lyman-α Emitters at the Epoch of Reionization: Spectroscopic Confirmation
Schaerer, Daniel; Sobral, David; Mobasher, Bahram +5 more
Faint Lyα emitters become increasingly rarer toward the reionization epoch (z ∼ 6-7). However, observations from a very large (∼5 deg2) Lyα narrow-band survey at z = 6.6 show that this is not the case for the most luminous emitters, capable of ionizing their own local bubbles. Here we present follow-up observations of the two most lumin…
The Relation between Star Formation Rate and Stellar Mass for Galaxies at 3.5 <= z <= 6.5 in CANDELS
Papovich, Casey; Finkelstein, Steven L.; Dickinson, Mark +15 more
Distant star-forming galaxies show a correlation between their star formation rates (SFRs) and stellar masses, and this has deep implications for galaxy formation. Here, we present a study on the evolution of the slope and scatter of the SFR-stellar mass relation for galaxies at 3.5 <= z <= 6.5 using multi-wavelength photometry in GOODS-S fr…
Using Lyman-α to detect galaxies that leak Lyman continuum
Verhamme, Anne; Hayes, Matthew; Schaerer, Daniel +1 more
Aims: We propose to infer the output of the ionising continuum-leaking properties of galaxies based upon their Lyα line profiles.
Methods: We carried out Lyα radiation transfer calculations in two models of H ii regions. These models are porous to ionising continuum escape: 1) we define Lyman-continuum (LyC) optically thin star clusters,…
Small-scale filament eruptions as the driver of X-ray jets in solar coronal holes
Moore, Ronald L.; Sterling, Alphonse C.; Falconer, David A. +1 more
Solar X-ray jets are thought to be made by a burst of reconnection of closed magnetic field at the base of a jet with ambient open field. In the accepted version of the `emerging-flux' model, such a reconnection occurs at a plasma current sheet between the open field and the emerging closed field, and also forms a localized X-ray brightening that …
Calibration of the NuSTAR High-energy Focusing X-ray Telescope.
An, Hongjun; Hailey, Charles J.; Walton, Dominic J. +19 more
We present the calibration of the Nuclear Spectroscopic Telescope Array (NuSTAR) X-ray satellite. We used the Crab as the primary effective area calibrator and constructed a piece-wise linear spline function to modify the vignetting response. The achieved residuals for all off-axis angles and energies, compared to the assumed spectrum, are typical…