Search Publications
Structure and physical conditions in the Huygens region of the Orion nebula
O'Dell, C. R.; Ferland, G. J.; Peimbert, M.
Hubble Space Telescope images, MUSE maps of emission lines, and an atlas of high velocity resolution emission-line spectra have been used to establish for the first time correlations of the electron temperature, electron density, radial velocity, turbulence, and orientation within the main ionization front of the nebula. From the study of the comb…
The Optical Counterpart to the Accreting Millisecond X-Ray Pulsar SAX J1748.9-2021 in the Globular Cluster NGC 6440
Dalessandro, E.; Ferraro, F. R.; Lanzoni, B. +3 more
We used a combination of deep optical and {{H}}α images of the Galactic globular cluster NGC 6440, acquired with the Hubble Space Telescope, to identify the optical counterpart to the accreting millisecond X-ray pulsar SAX J1748.9-2021 during quiescence. A strong {{H}}α emission has been detected from a main-sequence star (hereafter COM-SAX J1748.…
Photoionization-driven Absorption-line Variability in Balmer Absorption Line Quasar LBQS 1206+1052
Wang, Jianguo; Zhou, Hongyan; Ji, Tuo +10 more
In this paper we present an analysis of absorption-line variability in mini-BAL quasar LBQS 1206+1052. The Sloan Digital Sky Survey spectrum demonstrates that the absorption troughs can be divided into two components of blueshift velocities of ∼700 and ∼1400 km s-1 relative to the quasar rest frame. The former component shows rare Balme…
XMM-Newton Observation of the nearby Pulsar B1133+16.
Haberl, Frank; Mitra, Dipanjan; Zhang, Bing +5 more
We constrain the X-ray properties of the nearby (360 {pc}), old (5 {Myr}) pulsar B1133+16 with ∼ 100 {ks} effective exposure time by XMM-Newton. The observed pulsar flux in the 0.2-3 keV energy range is ∼ {10}-14 {erg} {cm}}-2 {{{s}}}-1, which results in the recording of ∼600 source counts with the EPIC pn and MOS …
Lighthouse in the dust: infrared echoes of periodic emission from massive black hole binaries★
Haiman, Zoltán; D'Orazio, Daniel J.
The optical and UV emission from sub-parsec massive black hole binaries (MBHBs) in active galactic nuclei (AGNs) is believed to vary periodically, on time-scales comparable to the binary's orbital time. If driven by accretion rate fluctuations, the variability could be isotropic. If dominated by relativistic Doppler modulation, the variability sho…
A revised moving cluster distance to the Pleiades open cluster
Bouy, H.; Bouvier, J.; Teixeira, R. +3 more
Context. The distance to the Pleiades open cluster has been extensively debated in the literature over several decades. Although different methods point to a discrepancy in the trigonometric parallaxes produced by the HIPPARCOS mission, the number of individual stars with known distances is still small compared to the number of cluster members to …
In and out star formation in z 1.5 quiescent galaxies from rest-frame UV spectroscopy and the far-infrared
Cimatti, A.; Daddi, E.; Béthermin, M. +18 more
We present a sample of 34 spectroscopically confirmed BzK-selected 1011M⊙ quiescent galaxies (pBzK) in the COSMOS field. The targets were initially observed with VIMOS on the VLT to facilitate the calibration of the photometric redshifts of massive galaxies at z ≳ 1.5. Here we describe the reduction and analysis of the data, …
Understanding Problem Forecasts of ISEST Campaign Flare-CME Events
Nitta, Nariaki; Webb, David
The goal of the International Study of Earth-affecting Solar Transients (ISEST) project as part of the Variability of the Sun and Its Terrestrial Impact (VarSITI) program is to understand the origin, evolution, and propagation of solar transients through the space between the Sun and Earth, and to improve our prediction capability for space weathe…
The Optical-Mid-infrared Extinction Law of the l = 165° Sightline in the Galactic Plane: Diversity of the Extinction Law in the Diffuse Interstellar Medium
Wang, Shu; de Grijs, Richard; Zhao, He +2 more
Understanding the effects of dust extinction is important to properly interpret observations. The optical total-to-selective extinction ratio, {R}V={A}V/E(B-V), is widely used to describe extinction variations in ultraviolet and optical bands. Since the {R}V=3.1 extinction curve adequately represents the average ex…
Plasma Environment around Comet 67P/Churyumov-Gerasimenko at Perihelion: Model Comparison with Rosetta Data
Altwegg, K.; Goetz, C.; Goldstein, R. +6 more
The plasma environment near comet 67P/Churyumov-Gerasimenko (67P/CG) is dynamically affected by various factors, including the incident solar wind and outgassing from the nucleus. The Rosetta spacecraft MAGnetometer (MAG) instrument observations near perihelion showed crossing events into a magnetic field-free region at about 170 km from the nucle…