Search Publications
The X-Ray Luminosity Function of Low-mass X-Ray Binaries in Early-type Galaxies, Their Metal-rich, and Metal-poor Globular Clusters
Zepf, Stephen E.; Peacock, Mark B.
We present the X-ray luminosity function (XLF) of low-mass X-ray binaries (LMXBs) in the globular clusters (GCs) and fields of seven early-type galaxies. These galaxies are selected to have both deep Chandra observations, which allow their LMXB populations to be observed to X-ray luminosities of 1037-1038 erg s-1, …
Emergence of Granular-sized Magnetic Bubbles Through the Solar Atmosphere. III. The Path to the Transition Region
De Pontieu, Bart; Carlsson, Mats; Ortiz, Ada +4 more
We study, for the first time, the ascent of granular-sized magnetic bubbles from the solar photosphere through the chromosphere into the transition region and above. Such events occurred in a flux emerging region in NOAA 11850 on 2013 September 25. During that time, the first co-observing campaign between the Swedish 1-m Solar Telescope (SST) and …
BICEP2/Keck Array. VII. Matrix Based E/B Separation Applied to Bicep2 and the Keck Array
Ade, P. A. R.; Bock, J. J.; Crill, B. P. +62 more
A linear polarization field on the sphere can be uniquely decomposed into an E-mode and a B-mode component. These two components are analytically defined in terms of spin-2 spherical harmonics. Maps that contain filtered modes on a partial sky can also be decomposed into E-mode and B-mode components. However, the lack of full sky information preve…
On the Evolution of the Inner Disk Radius with Flux in the Neutron Star Low-mass X-Ray Binary Serpens X-1
Miller, Jon M.; Cackett, Edward M.; Strohmayer, Tod E. +3 more
We analyze the latest Suzaku observation of the bright neutron star (NS) low-mass X-ray binary Serpens X-1 taken in 2013 October and 2014 April. The observation was taken using the burst mode and only suffered mild pile-up effects. A broad iron line is clearly detected in the X-ray spectrum. We test different models and find that the iron line is …
Multi-wavelength Polarimetry and Spectral Study of the M87 Jet During 2002-2008
Perlman, Eric S.; Cara, Mihai; Sparks, William B. +4 more
We present a multi-wavelength polarimetric and spectral study of the M87 jet obtained at sub-arcsecond resolution between 2002 and 2008. The observations include multi-band archival VLA polarimetry data sets along with Hubble Space Telescope (HST) imaging polarimetry. These observations have better angular resolution than previous work by factors …
Improving the Flux Calibration in Reverberation Mapping by Spectral Fitting:Application to the Seyfert Galaxy MCG-6-30-15
Ho, Luis C.; Du, Pu; Hu, Chen +4 more
We propose a method for the flux calibration of reverberation mapping spectra, based on accurate measurement of [O III] λ5007 emission by spectral fitting. Our method can achieve better accuracy than the traditional method of Groningen & Wanders, allowing reverberation mapping measurements for objects with variability amplitudes as low as ∼5%.…
Hard X-Ray Emissions from Cassiopeia A Observed by INTEGRAL
Wang, Wei; Li, Zhuo
Cassiopeia A (Cas A), as the nearby young remnant of a core-collapse supernova, is the best candidate for astrophysical studies in supernova explosion and its environment. We studied the hard X-ray emission from Cas A using the 10 year data of INTEGRAL observations, and first detected non-thermal continuum emission from the source up to 220 keV. T…
MHD-Kinetic Transition in Imbalanced Alfvénic Turbulence
De Keyser, Johan; Voitenko, Yuriy
Alfvénic turbulence in space is usually imbalanced: amplitudes of waves propagating parallel and anti-parallel to the mean magnetic field {{\boldsymbol{B}}}0 are unequal. It is commonly accepted that the turbulence is driven by (counter-)collisions between these counter-propagating wave fractions. Contrary to this, we found a new ion-sc…
A Search for Short-period Rocky Planets around WDs with the Cosmic Origins Spectrograph (COS)
Debes, John H.; Hines, Dean C.; Bourque, Matthew +2 more
The search for transiting habitable exoplanets has broadened to include several types of stars that are smaller than the Sun in an attempt to increase the observed transit depth and hence the atmospheric signal of the planet. Of all spectral types, white dwarfs (WDs) are the most favorable for this type of investigation. The fraction of WDs that p…
On Understanding the Nature of Collisions of Coronal Mass Ejections Observed by STEREO
Wang, Yuming; Srivastava, Nandita; Mishra, Wageesh
We attempt to understand the collision characteristics of two coronal mass ejections (CMEs) launched successively from the Sun on 2013 October 25. The estimated kinematics, from three-dimensional (3D) reconstruction techniques applied to observations of CMEs by the SECCHI/Coronagraphic (COR) and Heliospheric Imagers, reveal their collision around …