Search Publications
Galaxy Cluster Baryon Fractions Revisited
Zabludoff, Ann I.; Gonzalez, Anthony H.; Zaritsky, Dennis +1 more
We measure the baryons contained in both the stellar and hot-gas components for 12 galaxy clusters and groups at z ~ 0.1 with M = 1-5 × 1014 M ⊙. This paper improves upon our previous work through the addition of XMM-Newton X-ray data, enabling measurements of the total mass and masses of each major baryonic component—intracl…
Measurement of the Radius of Neutron Stars with High Signal-to-noise Quiescent Low-mass X-Ray Binaries in Globular Clusters
Guillot, Sebastien; Webb, Natalie A.; Servillat, Mathieu +1 more
This paper presents the measurement of the neutron star (NS) radius using the thermal spectra from quiescent low-mass X-ray binaries (qLMXBs) inside globular clusters (GCs). Recent observations of NSs have presented evidence that cold ultra dense matter—present in the core of NSs—is best described by "normal matter" equations of state (EoSs). Such…
Cosmological Constraints from Sunyaev-Zel'dovich-selected Clusters with X-Ray Observations in the First 178 deg2 of the South Pole Telescope Survey
Gladders, M. D.; Rest, A.; Foley, R. J. +77 more
We use measurements from the South Pole Telescope (SPT) Sunyaev-Zel'dovich (SZ) cluster survey in combination with X-ray measurements to constrain cosmological parameters. We present a statistical method that fits for the scaling relations of the SZ and X-ray cluster observables with mass while jointly fitting for cosmology. The method is generali…
Joint Analysis of Cluster Observations. II. Chandra/XMM-Newton X-Ray and Weak Lensing Scaling Relations for a Sample of 50 Rich Clusters of Galaxies
Hoekstra, Henk; Babul, Arif; Mahdavi, Andisheh +3 more
We present a study of multiwavelength X-ray and weak lensing scaling relations for a sample of 50 clusters of galaxies. Our analysis combines Chandra and XMM-Newton data using an energy-dependent cross-calibration. After considering a number of scaling relations, we find that gas mass is the most robust estimator of weak lensing mass, yielding 15%…
The Structure of the Milky Way's Hot Gas Halo
Bregman, Joel N.; Miller, Matthew J.
The Milky Way's million degree gaseous halo contains a considerable amount of mass that, depending on its structural properties, can be a significant mass component. In order to analyze the structure of the Galactic halo, we use XMM-Newton Reflection Grating Spectrometer archival data and measure O VII Kα absorption-line strengths toward 26 active…
The Ultra-long Gamma-Ray Burst 111209A: The Collapse of a Blue Supergiant?
Piro, L.; D'Elia, V.; Cutini, S. +8 more
We present optical, X-ray and gamma-ray observations of GRB 111209A, observed at a redshift of z = 0.677. We show that this event was active in its prompt phase for about 25000 s, making it the longest burst ever observed. This rare event could have been detected up to z ~ 1.4 in gamma-rays. Compared to other long gamma-ray bursts (GRBs), GRB 1112…
The Ultraluminous X-Ray Sources NGC 1313 X-1 and X-2: A Broadband Study with NuSTAR and XMM-Newton
Hailey, Charles J.; Fabian, Andrew C.; Fürst, Felix +16 more
We present the results of NuSTAR and XMM-Newton observations of the two ultraluminous X-ray sources: NGC 1313 X-1 and X-2. The combined spectral bandpass of the two satellites enables us to produce the first spectrum of X-1 between 0.3 and 30 keV, while X-2 is not significantly detected by NuSTAR above 10 keV. The NuSTAR data demonstrate that X-1 …
The Spin-down of PSR J0821-4300 and PSR J1210-5226: Confirmation of Central Compact Objects as Anti-magnetars
Gotthelf, E. V.; Halpern, J. P.; Alford, J.
Using XMM-Newton and Chandra, we measure period derivatives for the second and third known pulsars in the class of central compact objects (CCOs) in supernova remnants, proving that these young neutron stars have exceptionally weak dipole magnetic field components. For the 112 ms PSR J0821-4300 in Puppis A, \dot{P} = (9.28 +/- 0.36) \times 10^{-18…
The Nearest Millisecond Pulsar Revisited with XMM-Newton: Improved Mass-radius Constraints for PSR J0437-4715
Bogdanov, Slavko
I present an analysis of the deepest X-ray exposure of a radio millisecond pulsar (MSP) to date, an X-ray Multi Mirror-Newton European Photon Imaging Camera spectroscopic and timing observation of the nearest known MSP, PSR J0437-4715. The timing data clearly reveal a secondary broad X-ray pulse offset from the main pulse by ~0.55 in rotational ph…
The Outburst Decay of the Low Magnetic Field Magnetar SGR 0418+5729
Tiengo, A.; Götz, D.; Stella, L. +20 more
We report on the long-term X-ray monitoring of the outburst decay of the low magnetic field magnetar SGR 0418+5729 using all the available X-ray data obtained with RXTE, Swift, Chandra, and XMM-Newton observations from the discovery of the source in 2009 June up to 2012 August. The timing analysis allowed us to obtain the first measurement of the …