Search Publications
Test for Wavevector Anisotropies in Plasma Turbulence Cascades
Gary, S. Peter
The frequency and wavevector matching conditions in nonlinear three-wave coupling are used to test whether the forward cascade of plasma turbulence may lead to wavevector anisotropies in a homogeneous, collisionless, magnetized plasma. Linear kinetic theory at β p = 0.01, 0.10, and 1.0 is used to determine the frequency-wavenumber disp…
Serendipitous Detection of X-Ray Emission from the Hot Born-again Central Star of the Planetary Nebula K 1-16
Kastner, Joel H.; Montez, Rodolfo, Jr.
We report the serendipitous detection of point-like X-ray emission from the hot, PG1159-type central star of the planetary nebula (CSPN) K 1-16 by the XMM-Newton and Chandra X-Ray Observatories. The CSPN lies superimposed on a galaxy cluster that includes an X-ray-bright quasar, but we have successfully isolated the CSPN X-ray emission from the st…
[Fe II] 1.64 µm Features of Jets and Outflows from Young Stellar Objects in the Carina Nebula
Lyo, A. -Ran; Pyo, Tae-Soo; Park, Byeong-Gon +11 more
We present [Fe II] 1.64 µm imaging observations for jets and outflows from young stellar objects (YSOs) over the northern part (~24' × 45') of the Carina Nebula, a massive star-forming region. The observations were performed with IRIS2 of the Anglo-Australian Telescope and the seeing was ~1.''5 ± 0.''5. Eleven jet and outflow features are de…
A Cluster Pair: A3532 and A3530
Singh, K. P.; Saikia, D. J.; Hunstead, R. W. +1 more
We present a detailed study of a close pair of clusters of galaxies, A3532 and A3530, and their environments. The Chandra X-ray image of A3532 reveals the presence of substructures on scales of ~20'' in its core. XMM-Newton maps of the clusters show excess X-ray emission from an overlapping region between them. Spectrally determined projected temp…
Insight into Active Galactic Nucleus and Host Galaxy Co-evolution from Hard X-Ray Emission
Wang, J.; Wei, J. Y.; Zhou, X. L.
We study the issue of active galactic nucleus (AGN) and host co-evolution by focusing on the correlation between the hard X-ray emission from central AGNs and the stellar populations of the host galaxies. Focusing on galaxies with strong Hα line emission (EW(Hα) > 5 Å), both X-ray and optical spectral analyses are performed on 67 (partially) ob…
The Second Ultraluminous X-Ray Source Transient in M31: Chandra, Hubble Space Telescope, and XMM Observations, and Evidence for an Extended Corona
Murray, S. S.; Barnard, R.; Garcia, M.
XMMU J004243.6+412519 is a transient X-ray source in M31, first discovered 2012 January 15. Different approaches to fitting the brightest follow-up observation gave luminosities 1.3-2.5 × 1039 erg s-1, making it the second ultraluminous X-ray source (ULX) in M31, with a probable black hole accretor. These different models rep…
Discovery of an Hα Emitting Disk around the Supermassive Black Hole of M31
Ricci, T. V.; Steiner, J. E.; Menezes, R. B.
Due to its proximity, the mass of the supermassive black hole in the nucleus of the Andromeda galaxy (M31), the most massive black hole in the Local Group of galaxies, has been measured by several methods involving the kinematics of a stellar disk which surrounds it. We report here the discovery of an eccentric Hα emitting disk around the black ho…
A Joint Model of X-Ray and Infrared Backgrounds. II. Compton-thick Active Galactic Nucleus Abundance
Armus, Lee; Helou, George; Shi, Yong
We estimate the abundance of Compton-thick (CT) active galactic nuclei (AGNs) based on our joint model of X-ray and infrared backgrounds. At L rest2-10 keV > 1042 erg s-1, the CT AGN density predicted by our model is a few ×10-4 Mpc-3 from z = 0 up to z = 3. CT AGNs with higher luminosity c…
The Planck Sunyaev-Zel'dovich versus the X-Ray View of the Coma Cluster
Lapi, A.; Cavaliere, A.; Fusco-Femiano, R.
The Planck collaboration has recently published precise and resolved measurements of the Sunyaev-Zel'dovich (SZ) effect in Abell 1656 (the Coma cluster of galaxies), thus directly gauging the electron pressure profile in the intracluster plasma. On the other hand, such a quantity may be also derived from combining the density and temperature provi…
A Magnetic Reconnection Origin for the Soft X-Ray Excess in an Active Galactic Nucleus
Wang, Jiancheng; Zhong, Xiaogu
We present a new scenario to explain the soft X-ray excess in an active galactic nucleus (AGN). Magnetic reconnection could happen in a thin layer on the surface of an accretion disk. Electrons are accelerated by a shock wave and turbulence is triggered by magnetic reconnection. Inverse Compton scattering then takes place above the accretion disk,…