Search Publications
Broad-line region clouds orbiting an AGN sample
Logan, C. H. A.; Llerena, M.; Armijos-Abendaño, J. +1 more
We present a spectral and temporal analysis of XMM-Newton data from a sample of six galaxies (NGC 3783, Mrk 279, Mrk 766, NGC 3227, NGC 7314, and NGC 3516). Using the hardness-ratio curves, we identify time intervals in which clouds are eclipsing the central X-ray source in five of the six sources. We detect three occultations in NGC 3227 and one …
Radial profiles of lensed z ∼ 1 galaxies on sub-kiloparsec scales
Richard, Johan; Chisholm, John; Schaerer, Daniel +4 more
We study the spatially resolved physical properties of the Cosmic Snake arc in MACS J1206.2-0847 and the arc in Abell 0521 (A521). These are two strongly lensed galaxies at redshifts z = 1.036 and z = 1.044. We used observations of the Hubble Space Telescope (HST) and the Atacama Large Millimeter/submillimeter Array (ALMA). The former gives access…
Kinematics of the Central Stars Powering Bowshock Nebulae and the Large Multiplicity Fraction of Runaway OB Stars
Kobulnicky, Henry A.; Chick, William T.
OB stars powering stellar bowshock nebulae (SBNe) have been presumed to have large peculiar velocities. We measured peculiar velocities of SBN central stars to assess their kinematics relative to the general O-star population using Gaia EDR3 data for 267 SBN central stars and a sample of 455 Galactic O stars to derive projected velocities v 2…
Probing modified Newtonian dynamics with hypervelocity stars
Gallo, Arianna; Ostorero, Luisa; Chakrabarty, Sankha Subhra +2 more
We show that measuring the velocity components of hypervelocity stars (HVSs) can discriminate between modified Newtonian dynamics (MOND) and Newtonian gravity. Hypervelocity stars are ejected from the Galactic center on radial trajectories with a null tangential velocity component in the reference frame of the Galaxy. They acquire tangential compo…
Tomography of the environment of the COSMOS/AzTEC-3 submillimeter galaxy at z ∼ 5.3 revealed by Lyα and MUSE observations
Dannerbauer, H.; Marino, R.; da Cunha, E. +8 more
Context. Submillimeter galaxies (SMGs) have been proposed as the progenitors of massive ellipticals in the local Universe. Mapping the neutral gas distribution and investigating the gas accretion toward the SMGs at high redshift can provide information on the way SMG environments can evolve into clusters at z = 0.
Aims: In this work, we study…
A Review of the Extended EUV Corona Observed by the Sun Watcher with Active Pixels and Image Processing (SWAP) Instrument
Berghmans, David; West, Matthew J.; Mierla, Marilena +7 more
The Sun Watcher with Active Pixels and Image Processing (SWAP) instrument onboard ESA's PRoject for On Board Autonomy 2 (PROBA2) has provided the first uncompressed, high-cadence, continuous, large field-of-view observations of the extended extreme-ultraviolet (EUV) corona for over a complete solar cycle. It has helped shape our understanding of t…
Identifying the 3FHL Catalog. VI. Swift Observations of 3FHL Unassociated Objects with Source Classification via Machine Learning
Ajello, M.; Marchesi, S.; Torres-Albà, N. +5 more
The Third Catalog of Hard Fermi Large Area Telescope Sources (3FHL) reports the detection of 1556 objects at E > 10 GeV. However, 177 sources remain unassociated and 23 are associated with a ROSAT X-ray detection of unknown origin. Pointed X-ray observations were conducted on 30 of these unassociated and unknown sources with Swift-XRT. A bright…
The Global Structure of the Milky Way's Stellar Halo Based on the Orbits of Local Metal-poor Stars
Chiba, Masashi; Sato, Genta
We analyze the global structure of the Milky Way (MW)'s stellar halo, including its dominant subcomponent, Gaia-Sausage-Enceladus (GSE). The method for reconstructing the global distribution of this old stellar component is to employ the superposition of the orbits covering the large MW's space, where each of the orbit-weighting factors is assigne…
The Physical Properties of Massive Green Valley Galaxies as a Function of Environments at 0.5 < z < 2.5 in 3D-HST/Candels Fields
Fang, Guanwen; Lin, Zesen; Kong, Xu +3 more
To investigate the effects of environment in the quenching phase, we study the empirical relations for green valley (GV) galaxies between overdensity and other physical properties (i.e., effective radius r e , Sérsic indices n, and specific star formation rate (sSFR)). Based on five 3D-HST/CANDELS fields, we construct a large sample of …
Data reduction and restoration of spectropolarimetric microlensed hyperspectral imager data
van Noort, M.; Doerr, H. -P.
Context. A microlensed hyperspectral imager (MiHI) is an integral field spectrograph based on a double-sided microlens array.
Aims: To convert the raw data frames of such an instrument to hyperspectral cubes, and restore them to high-resolution science-ready Stokes data, a new kind of data reduction procedure is required.
Methods: An opt…