Search Publications
Evidence for a Merger-induced Shock Wave in ZwCl 0008.8+5215 with Chandra and Suzaku
Di Gennaro, G.; Brunetti, G.; Forman, W. +8 more
We present the results from new deep Chandra (∼410 ks) and Suzaku (∼180 ks) observations of the merging galaxy cluster ZwCl 0008.8+5215 (z = 0.104). Previous radio observations revealed the presence of a double radio relic located diametrically west and east of the cluster center. Using our new Chandra data, we find evidence for the presence of a …
The Structure of Solar Coronal Mass Ejections in the Extreme-ultraviolet Passbands
Chen, Y.; Song, H. Q.; Zhang, J. +5 more
So far, most studies on the structure of coronal mass ejections (CMEs) are conducted through white-light coronagraphs, demonstrating that about one third of CMEs exhibit the typical three-part structure in the high corona (e.g., beyond 2 {R}⊙ ), i.e., the bright front, the dark cavity, and the bright core. In this paper, we address the …
The Expansion of the Forward Shock of 1E 0102.2-7219 in X-Rays
Hughes, John P.; Plucinsky, Paul P.; Patnaude, Daniel J. +2 more
We measure the expansion of the forward shock of the Small Magellanic Cloud supernova remnant 1E 0102.2-7219 in X-rays using Chandra X-Ray Observatory on-axis Advanced CCD Imaging Spectrometer observations from 1999 to 2016. We estimate an expansion rate of 0.025% ± 0.006% yr-1 and a blast wave velocity of (1.61+/- 0.37)× {10}3
Tidal-locking-induced Stellar Rotation Dichotomy in the Open Cluster NGC 2287?
Deng, Licai; de Grijs, Richard; Li, Chengyuan +1 more
Stars spend most of their lifetimes on the “main sequence” (MS) in the Hertzsprung-Russell diagram. The obvious double MSs seen in the equivalent color-magnitude diagrams characteristic of Milky Way open clusters (OCs) pose a fundamental challenge to our traditional understanding of star clusters as “single stellar populations.” The clear MS bifur…
FUGIN: Molecular Gas in Spitzer Bubble N4—Possible Evidence for a Cloud-Cloud Collision as a Trigger of Massive Star Formations
Yamagishi, Mitsuyoshi; Kuno, Nario; Tachihara, Kengo +17 more
Herein, we present 12CO (J = 1-0) and 13CO (J = 1-0) emission-line observations via the FOREST Unbiased Galactic plane Imaging survey with the Nobeyama 45 m telescope (FUGIN) toward Spitzer bubble N4. We observed clouds at three discrete velocities: 16, 19, and 25 km s-1. Their masses were 0.1 × 104 M
A Broadband Look at the Old and New ULXs of NGC 6946
Fürst, Felix; Walton, Dominic J.; Stern, Daniel +8 more
Two recent observations of the nearby galaxy NGC 6946 with NuSTAR, one simultaneous with an XMM-Newton observation, provide an opportunity to examine its population of bright accreting sources from a broadband perspective. We study the three known ultraluminous X-ray sources (ULXs) in the galaxy, and find that ULX-1 and ULX-2 have very steep power…
Testing the Kerr Metric with X-Ray Reflection Spectroscopy of Mrk 335 Suzaku Data
Abdikamalov, Askar B.; Ayzenberg, Dimitry; Bambi, Cosimo +4 more
Einstein’s gravity has undergone extensive tests in the weak field gravitational limit, with results in agreement with theoretical predictions. There exist theories beyond general relativity (GR) which modify gravity in the strong field regime but agree with GR in the weak field. Astrophysical black holes are believed to be described by the Kerr m…
Statistics on the Magnetosheath Properties Related to Magnetopause Magnetic Reconnection
Zhang, Hui; Liu, Libo; Wan, Weixing +5 more
Magnetosheath properties, particularly those related to magnetopause magnetic reconnection (MR), are investigated in this study. (1) Asymmetries are found to exist in the distributions of plasma and magnetic field parameters in the magnetosheath. These asymmetries are related to the interplanetary magnetic field (IMF) orientation, and they are pro…
A Detailed Study of the Most Relaxed SPT-selected Galaxy Clusters: Properties of the Cool Core and Central Galaxy
Schrabback, T.; Hlavacek-Larrondo, J.; Bayliss, M. +14 more
We present a multi-wavelength analysis of the four most relaxed clusters in the South Pole Telescope 2500 deg2 survey, which lie at 0.55 < z < 0.75. This study, which utilizes new, deep data from the Chandra X-ray Observatory and Hubble Space Telescope, along with ground-based spectroscopy from Gemini and Magellan, improves signif…
Frequency-Distance Structure of Solar Radio Sources Observed by LOFAR
Browning, Philippa; Gordovskyy, Mykola; Kontar, Eduard +1 more
Low-frequency radio observations make it possible to study the solar corona at distances up to 2-3 R ⊙. Frequency of plasma emission is a proxy for electron density of the emitting plasma and, therefore, observations of solar radio bursts can be used to probe the density structure of the outer corona. In this study, positions of solar r…