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Molecular ions in the protostellar shock L1157-B1
Podio, L.; Codella, C.; Ceccarelli, C. +2 more
Aims: We perform a complete census of molecular ions with an abundance greater than ~10-10 in the protostellar shock L1157-B1. This allows us to study the ionisation structure and chemistry of the shock.
Methods: An unbiased high-sensitivity survey of L1157-B1 performed with the IRAM-30 m and Herschel/HIFI as part of the CHESS…
Nitrogen Abundances and Multiple Stellar Populations in the Globular Clusters of the Fornax dSph
Brodie, Jean P.; Strader, Jay; Larsen, Søren S. +1 more
We use measurements of nitrogen abundances in red giants to search for multiple stellar populations in the four most metal-poor globular clusters (GCs) in the Fornax dwarf spheroidal galaxy (Fornax 1, 2, 3, and 5). New imaging in the F343N filter, obtained with the Wide Field Camera 3 on the Hubble Space Telescope, is combined with archival F555W …
NuSTAR Reveals an Intrinsically X-Ray Weak Broad Absorption Line Quasar in the Ultraluminous Infrared Galaxy Markarian 231
Rigby, J. R.; Veilleux, S.; Harrison, F. A. +24 more
We present high-energy (3-30 keV) NuSTAR observations of the nearest quasar, the ultraluminous infrared galaxy (ULIRG) Markarian 231 (Mrk 231), supplemented with new and simultaneous low-energy (0.5-8 keV) data from Chandra. The source was detected, though at much fainter levels than previously reported, likely due to contamination in the large ap…
Globular Cluster Systems in Brightest Cluster Galaxies: A Near-universal Luminosity Function?
Bailin, Jeremy; Whitmore, Bradley C.; Côté, Patrick +10 more
We present the first results from our Hubble Space Telescope brightest cluster galaxy (BCG) survey of seven central supergiant cluster galaxies and their globular cluster (GC) systems. We measure a total of 48,000 GCs in all seven galaxies, representing the largest single GC database. We find that a log-normal shape accurately matches the observed…
Observations of Environmental Quenching in Groups in the 11 GYR since z = 2.5: Different Quenching for Central and Satellite Galaxies
van Dokkum, Pieter G.; Franx, Marijn; Illingworth, Garth D. +16 more
We present direct observational evidence for star formation quenching in galaxy groups in the redshift range 0 < z < 2.5. We utilize a large sample of nearly 6000 groups, selected by fixed cumulative number density from three photometric catalogs, to follow the evolving quiescent fractions of central and satellite galaxies over roughly 11 Gy…
Measurement of Galaxy Clustering at z ~ 7.2 and the Evolution of Galaxy Bias from 3.8 < z < 8 in the XDF, GOODS-S, and GOODS-N
Trenti, M.; Oesch, P. A.; Carollo, C. M. +8 more
Lyman-break galaxy (LBG) samples observed during reionization (z >~ 6) with the Hubble Space Telescope's Wide Field Camera 3 are reaching sizes sufficient to characterize their clustering properties. Using a combined catalog from the Hubble eXtreme Deep Field and CANDELS surveys, containing N = 743 LBG candidates at z >= 6.5 at a mean redshi…
Detection of warm and diffuse baryons in large scale structure from the cross correlation of gravitational lensing and the thermal Sunyaev-Zeldovich effect
Van Waerbeke, Ludovic; Hinshaw, Gary; Murray, Norman
We report the first detection of a correlation between gravitational lensing by large scale structure and the thermal Sunyaev-Zeldovich (tSZ) effect. Using the mass map from the Canada France Hawaii Telescope Lensing Survey and a newly constructed tSZ map from Planck, we measure a nonzero correlation between the two maps out to one degree angular …
Evolution of Thermally Pulsing Asymptotic Giant Branch Stars. IV. Constraining Mass loss and Lifetimes of Low Mass, Low Metallicity AGB Stars
Williams, Benjamin F.; Dolphin, Andrew; Girardi, Léo +7 more
The evolution and lifetimes of thermally pulsating asymptotic giant branch (TP-AGB) stars suffer from significant uncertainties. In this work, we analyze the numbers and luminosity functions of TP-AGB stars in six quiescent, low metallicity ([Fe/H] <~ -0.86) galaxies taken from the ACS Nearby Galaxy Survey Treasury sample, using Hubble Space Te…
The neutron star transient and millisecond pulsar in M28: from sub-luminous accretion to rotation-powered quiescence
Heinke, Craig; Bahramian, Arash; Homan, Jeroen +6 more
The X-ray transient IGR J18245-2452 in the globular cluster M28 contains the first neutron star (NS) seen to switch between rotation-powered and accretion-powered pulsations. We analyse its 2013 March-April 25 d long outburst as observed by Swift, which had a peak bolometric luminosity of ∼6 per cent of the Eddington limit (LEdd), and g…
Iron Kα emission in type-I and type-II active galactic nuclei
Paltani, S.; Gandhi, P.; Ricci, C. +3 more
The narrow Fe Kα line is one of the main signatures of the reprocessing of X-ray radiation from the material surrounding supermassive black holes, and it has been found to be omnipresent in the X-ray spectra of active galactic nuclei (AGN). In this work, we study the characteristics of the narrow Fe Kα line in different types of AGN. Using the res…