Search Publications
Determination of an Upper Limit for the Water Outgassing Rate of Main-belt Comet P/2012 T1 (PANSTARRS)
Hartogh, P.; Teyssier, D.; Biver, N. +8 more
A new Main-Belt Comet (MBC) P/2012 T1 (PANSTARRS) was discovered on 2012 October 6, approximately one month after its perihelion, by the Pan-STARRS1 survey based in Hawaii. It displayed cometary activity upon its discovery with one hypothesis being that the activity was driven by sublimation of ices; as a result, we searched for emission assumed t…
Diffuse light in the young cluster of galaxies CL J1449+0856 at z = 2.07
Adami, C.; Durret, F.; Guennou, L. +1 more
Context. Cluster properties do not seem to be changing significantly during their mature evolution phase; for example, they do not seem to show any strong dynamical evolution at least up to z ~ 0.5, their galaxy red sequence is already in place at least up to z ~ 1.2, and their diffuse light content remains stable up to z ~ 0.8. The question is no…
The Emission Measure Distribution of Impulsive Phase Flare Footpoints
Fletcher, L.; Hannah, I. G.; Milligan, R. O. +1 more
The temperature distribution of the emitting plasma is a crucial constraint when studying the heating of solar flare footpoints. However, determining this for impulsive phase footpoints has been difficult in the past due to insufficient spatial resolution to resolve the footpoints from the loop structures, and a lack of spectral and temporal cover…
Short-term Variability of X-Rays from Accreting Neutron Star Vela X-1. I. Suzaku Observations
Makishima, Kazuo; Takahashi, Tadayuki; Odaka, Hirokazu +3 more
We have analyzed the time variability of the wide-band X-ray spectrum of Vela X-1, the brightest wind-fed accreting neutron star, on a short timescale of 2 ks by using Suzaku observations with an exposure of 100 ks. During the observation, the object showed strong variability, including several flares and so-called "low states," in which the X-ray…
The Mid-infrared Emission of Narrow-line Active Galactic Nuclei: Star Formation, Nuclear Activity, and Two Populations Revealed by Wise
Burtscher, Leonard; Lutz, Dieter; Rosario, David J. +3 more
We explore the nature of the long-wavelength mid-infrared (MIR) emission of a sample of 13,000 local Type II (narrow-line) active galactic nuclei (AGNs) from the Sloan Digital Sky Survey (SDSS) using 12 µm and 22 µm photometry from the WISE all-sky survey. In combination with FIRST 1.4 GHz photometry, we show that AGNs divide into two …
The circumstellar environment and evolutionary state of the supergiant B[e] star Wd1-9
Negueruela, I.; Clark, J. S.; Ritchie, B. W.
Context. Historically, supergiant (sg)B[e] stars have been difficult to include in theoretical schemes for the evolution of massive OB stars.
Aims: The location of Wd1-9 within the coeval starburst cluster Westerlund 1 means that it may be placed into a proper evolutionary context and we therefore aim to utilise a comprehensive multiwavelengt…
Constraints on Titan's middle atmosphere ammonia abundance from Herschel/SPIRE sub-millimetre spectra
Hartogh, P.; Lellouch, E.; Irwin, P. G. J. +6 more
Sub-millimetre spectra measured with Herschel's SPIRE Fourier Transform Spectrometer were used to search for ammonia (NH3) in Titan's stratosphere. Observations were taken during 2010 and 2011, just after Titan's northern spring equinox, which occurred in mid-2009. In our analysis we used high spectral resolution data (0.074 cm-1
A High Resolution View of the Warm Absorber in the Quasar MR 2251-178
Turner, T. J.; Kraemer, S. B.; Crenshaw, D. M. +5 more
High resolution X-ray spectroscopy of the warm absorber in a nearby quasar, MR 2251-178 (z = 0.06398), is presented. The observations were carried out in 2011 using the Chandra High Energy Transmission Grating (HETG) and the XMM-Newton Reflection Grating Spectrometer, with net exposure times of approximately 400 ks each. A multitude of absorption …
Ordering of injection events within Saturnian SLS longitude and local time
Gurnett, D. A.; Hospodarsky, G. B.; Kennelly, T. J. +1 more
Periodicities similar to the Saturn kilometric radio (SKR) emissions have been observed throughout the magnetosphere in both the magnetic field and the plasma. An outstanding question is what mechanism links these periodicities between the inner and outer magnetospheres. It had been postulated that the interchange instability, where narrow injecti…
Milliarcsec-scale radio emission of ultraluminous X-ray sources: steady jet emission from an intermediate-mass black hole?
Farrell, S. A.; Mezcua, M.; Gladstone, J. C. +1 more
The origin of the high X-ray luminosities of most ultraluminous X-ray sources (ULXs) still remains poorly understood. Most of the scenarios proposed to explain their nature assume that ULXs are powered by accretion on to a black hole (BH). In this case, the detection of compact radio emission and the location of the ULXs in the Fundamental Plane (…