Search Publications
The prevalence of star formation as a function of Galactocentric radius
Moore, T. J. T.; Elia, D.; Molinari, S. +3 more
We present large-scale trends in the distribution of star-forming objects revealed by the Hi-GAL survey. As a simple metric probing the prevalence of star formation in Hi-GAL sources, we define the fraction of the total number of Hi-GAL sources with a 70 µm counterpart as the `star-forming fraction' or SFF. The mean SFF in the inner galactic…
Correlated X-ray/ultraviolet/optical variability in NGC 6814
Horne, Keith; Goad, Michael R.; Cackett, Edward M. +4 more
We present results of a three-month combined X-ray/UV/optical monitoring campaign of the Seyfert 1 galaxy NGC 6814. The object was monitored by Swift from June through August 2012 in the X-ray and UV bands and by the Liverpool Telescope from May through July 2012 in B and V. The light curves are variable and significantly correlated between waveba…
Chandra Observations of Outflows from PSR J1509-5850
Pavlov, George G.; Kargaltsev, Oleg; Klingler, Noel +3 more
PSR J1509-5850 is a middle-aged pulsar with a period of P ≈ 89 ms and spin-down power of \dot{E}=5.1× {10}35 erg s-1, at a distance of about 3.8 kpc. We report on deep Chandra X-ray Observatory observations of this pulsar and its pulsar wind nebula (PWN). In addition to the previously detected tail extending up to 7‧ southwes…
The global surface composition of 67P/Churyumov-Gerasimenko nucleus by Rosetta/VIRTIS. II) Diurnal and seasonal variability
Mottola, S.; Barucci, M. A.; Ip, W. -H. +24 more
VIRTIS-M observations of the nucleus of comet 67P/Churyumov-Gerasimenko acquired from 2014 August to 2015 May have been analysed to investigate surface temporal variability at both seasonal and diurnal scales. The measured reflectance spectra are studied by means of comet spectral indicators (CSI) such as slopes in the visible and infrared ranges,…
High-speed Bullet Ejections during the AGB-to-Planetary Nebula Transition: HST Observations of the Carbon Star, V Hydrae
Sahai, R.; Morris, M. R.; Scibelli, S.
The well-studied carbon star, V Hya, showing evidence for high-speed, collimated outflows and dense equatorial structures, is a key object in the study of the poorly understood transition of AGB stars into aspherical planetary nebulae. Using the Space Telescope Imaging Spectrograph instrument on board the Hubble Space Telescope, we have obtained h…
Structure of Prominence Legs: Plasma and Magnetic Field
Schmieder, B.; Labrosse, N.; López Ariste, A. +1 more
We investigate the properties of a “solar tornado” observed on 2014 July 15, and aim to link the behavior of the plasma to the internal magnetic field structure of the associated prominence. We made multi-wavelength observations with high spatial resolution and high cadence using SDO/AIA, the Interface Region Imaging Spectrograph (IRIS) spectrogra…
Axion Decay and Anisotropy of Near-IR Extragalactic Background Light
Gong, Yan; Cooray, Asantha; Mitchell-Wynne, Ketron +3 more
The extragalactic background light (EBL) is composed of the cumulative radiation from all galaxies and active galactic nuclei over cosmic history. In addition to point sources, the EBL also contains information from diffuse sources of radiation. The angular power spectra of the near-infrared intensities could contain additional signals, and a comp…
GeMS MCAO observations of the Galactic globular cluster NGC 2808: the absolute age
Massari, D.; Stetson, P. B.; Bono, G. +7 more
Context. Globular clusters are the oldest stellar systems in the Milky Way, and they probe the early epoch of the Galaxy formation. However, the uncertainties on their absolute age are still too large to soundly constrain how the Galactic structures have assembled.
Aims: The aim of this work is to obtain an accurate estimate of the absolute a…
Anatomy of the AGN in NGC 5548. VII. Swift study of obscuration and broadband continuum variability
Kaastra, J. S.; Kriss, G. A.; Bianchi, S. +16 more
We present our investigation into the long-term variability of the X-ray obscuration and optical-UV-X-ray continuum in the Seyfert 1 galaxy NGC 5548. In 2013 and 2014, the Swift observatory monitored NGC 5548 on average every day or two, with archival observations reaching back to 2005, totalling about 670 ks of observing time. Both broadband spec…
Typical Profiles and Distributions of Plasma and Magnetic Field Parameters in Magnetic Clouds at 1 AU
Mierla, M.; Zhukov, A. N.; Rodriguez, L. +9 more
Magnetic clouds (MCs) are a subset of interplanetary coronal mass ejections (ICMEs). They are important because of their simple internal magnetic field configuration, which resembles a magnetic flux rope, and because they represent one of the most geoeffective types of solar transients. In this study, we analyze their internal structure using a su…