Search Publications
Infrared polarimetry of Mrk 231: scattering off hot dust grains in the central core
Siebenmorgen, R.; Telesco, C. M.; Packham, C. +13 more
We present high-angular (0.17-0.35 arcsec) resolution imaging polarimetric observations of Mrk 231 in the 3.1 µm filter using MMT-Pol on the 6.5-m MMT, and in the 8.7, 10.3, and 11.6 µm filters using CanariCam on the 10.4-m Gran Telescopio CANARIAS. In combination with already published observations, we compile the 1-12 µm total …
Chandra X-ray observations of the hyper-luminous infrared galaxy IRAS F15307+3252
Iwasawa, K.; Fabian, A. C.; Gandhi, P. +6 more
Hyper-luminous infrared galaxies (HyLIRGs) lie at the extreme luminosity end of the IR galaxy population with LIR > 1013 L⊙. They are thought to be closer counterparts of the more distant sub-millimeter galaxies, and should therefore be optimal targets to study the most massive systems in formation. We present d…
On the lensed blazar B0218+357
Falomo, R.; Treves, A.; Scarpa, R. +2 more
We present an optical spectrum (λλ4000-10 500) of the lensed blazar B0218+357 secured at the 10 m GTC and aimed to investigate and clarify the properties of this intriguing system. We found that the emission line spectrum of the blazar is characterized by only one broad emission line that interpreted as Mg II 2800 Å yields z = 0.95. In addition, w…
The M 4 Core Project with HST - V. Characterizing the PSFs of WFC3/UVIS by focus★
Anderson, J.; Bedin, L. R.
As part of the astrometric Hubble Space Telescope (HST) large program GO-12911, we conduct an in-depth study to characterize the point spread function (PSF) of the Uv-VISual channel of the Wide Field Camera 3 (WFC3), as a necessary step to achieve the astrometric goals of the program. We extracted a PSF from each of the 589 deep exposures taken th…
Deep Chandra observations of NGC 7457, the X-ray point source populations of a low-mass early-type galaxy
Kundu, Arunav; Zepf, Stephen E.; Maccarone, Thomas J. +4 more
We present the X-ray point source population of NGC 7457 based on 124 ks of Chandra observations. Previous deep Chandra observations of low-mass X-ray binaries (LMXBs) in early-type galaxies have typically targeted the large populations of massive galaxies. NGC 7457 is a nearby, early-type galaxy with a stellar luminosity of 1.7× 10^{10}{L_{K{⊙}}}…
A hierarchical model for the ages of Galactic halo white dwarfs
Si, Shijing; van Dyk, David A.; von Hippel, Ted +3 more
In astrophysics, we often aim to estimate one or more parameters for each member object in a population and study the distribution of the fitted parameters across the population. In this paper, we develop novel methods that allow us to take advantage of existing software designed for such case-by-case analyses to simultaneously fit parameters of b…
Herschel/SPIRE observations of water production rates and ortho-to-para ratios in comets★
Swinyard, Bruce M.; Wilson, Thomas G.; Rawlings, Jonathan M. C.
This paper presents Herschel/SPIRE (Spectral and Photometric Imaging Receiver) spectroscopic observations of several fundamental rotational ortho- and para-water transitions seen in three Jupiter-family comets and one Oort-cloud comet. Radiative transfer models that include excitation by collisions with neutrals and electrons, and by solar infrare…
The NGC 454 system: anatomy of a mixed ongoing merger
Plana, H.; Marino, A.; Mazzei, P. +3 more
This paper focuses on NGC 454, a nearby interacting pair of galaxies (AM 0112-554, RR23), composed of an early-type (NGC 454 E) and a star-forming late-type companion (NGC 454 W). We aim at characterizing this wet merger candidate via a multi-λ analysis, from near-UV (NUV) to optical using Swift UV/Optical Telescope (UVOT), and mapping the H α int…
A transient, flat spectrum radio pulsar near the Galactic Centre
Degenaar, N.; Kerr, M.; Kramer, M. +6 more
Recent studies have shown possible connections between highly magnetized neutron stars ('magnetars'), whose X-ray emission is too bright to be powered by rotational energy, and ordinary radio pulsars. In addition to the magnetar SGR J1745-2900, one of the radio pulsars in the Galactic Centre (GC) region, PSR J1746-2850, had timing properties imply…
Variable quiescent state for the neutron-star X-ray transient SAX J1750.8-2900: not such a hot neutron star after all?
Wijnands, R.; Parikh, A. S.
We monitored the neutron star low-mass X-ray binary SAX J1750.8-2900 after the end of its 2015/2016 outburst using the X-ray Telescope (XRT) aboard Swift to detect possible post-outburst 'rebrightenings', similar to those seen after its 2008 outburst. We did not detect any rebrightening behaviour, suggesting that the physical mechanism behind the …