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Effects of the variability of the nucleus of NGC 1275 on X-ray observations of the surrounding intracluster medium
Fabian, A. C.; Pinto, C.; Russell, H. R. +2 more
The active galaxy NGC 1275 lies at the centre of the Perseus cluster of galaxies, which is the X-ray brightest cluster in the Sky. The nucleus shows large variability over the past few decades. We compile a light curve of its X-ray emission covering about 40 years and show that the bright phase around 1980 explains why the inner X-ray bubbles were…
The morphology of the sub-giant branch and red clump reveal no sign of age spreads in intermediate-age clusters
Bastian, N.; Niederhofer, F.
A recent surprise in stellar cluster research, made possible through the precision of Hubble Space Telescope photometry, was that some intermediate-age (1-2 Gyr) clusters in the Large and Small Magellanic Clouds have main-sequence turn-off (MSTO) widths that are significantly broader than would be expected for a simple stellar population (SSP). On…
First INTEGRAL Observations of V404 Cygni during the 2015 Outburst: Spectral Behavior in the 20-650 keV Energy Range
Ubertini, Pietro; Bazzano, Angela; Jourdain, Elisabeth +3 more
In 2015 June, the source V404 Cygni (= GS2023+38) underwent an extraordinary outburst. We present the results obtained during the first revolution dedicated to this target by the INTEGRAL mission and focus on the spectral behavior in the hard X-ray domain, using both SPI and IBIS instruments. The source exhibits extreme variability and reaches flu…
Dusty wind of W Hydrae. Multi-wavelength modelling of the present-day and recent mass loss
Waters, L. B. F. M.; de Koter, A.; Decin, L. +5 more
Context. Low- and intermediate-mass stars go through a period of intense mass-loss at the end of their lives, during the asymptotic giant branch (AGB) phase. While on the AGB a significant part, or even most, of their initial mass is expelled in a stellar wind. This process controls the final stages of the evolution of these stars and contributes …
Probing gravity at large scales through CMB lensing
Ho, Shirley; Alam, Shadab; Pullen, Anthony R.
We describe a methodology to probe gravity with the cosmic microwave background (CMB) lensing convergence κ, specifically by measuring EG, the ratio of the Laplacian of the gravitational scalar potential difference to the velocity divergence. Using CMB lensing instead of galaxy-galaxy lensing avoids intrinsic alignments while also lacki…
Propagating Disturbances in the Solar Corona and Spicular Connection
Pant, Vaibhav; Banerjee, Dipankar; Samanta, Tanmoy
Spicules are small, hairy-like structures seen at the solar limb, mainly at chromospheric and transition region lines. They generally live for 3-10 minutes. We study these spicules in a south polar region of the Sun with coordinated observations using the Interface Region Imaging Spectrograph (IRIS) and the Atmospheric Imaging Assembly (AIA) instr…
First measurement of H I 21 cm emission from a GRB host galaxy indicates a post-merger system
Kanekar, Nissim; Michałowski, Michał J.; Roychowdhury, Sambit +2 more
We report the detection and mapping of atomic hydrogen in H I 21 cm emission from ESO 184-G82, the host galaxy of the gamma-ray burst 980425. This is the first instance where H I in emission has been detected from a galaxy hosting a gamma-ray burst (GRB). ESO 184-G82 is an isolated galaxy and contains a Wolf-Rayet region close to the location of t…
Mg II Lines Observed During the X-class Flare on 29 March 2014 by the Interface Region Imaging Spectrograph
Heinzel, P.; Liu, W.; Kleint, L. +1 more
Mg II lines represent one of the strongest emissions from the chromospheric plasma during solar flares. In this article, we studied the Mg II lines observed during the X1 flare on 29 March 2014 (SOL2014-03-29T17:48) by the Interface Region Imaging Spectrograph (IRIS). IRIS detected large intensity enhancements of the Mg II h and k lines, subordina…
The AKARI 2.5-5.0 µm Spectral Atlas of Type-1 Active Galactic Nuclei: Black Hole Mass Estimator, Line Ratio, and Hot Dust Temperature
Nakagawa, Takao; Oyabu, Shinki; Ohyama, Youichi +11 more
We present 2.5-5.0 µm spectra of 83 nearby (0.002 < z < 0.48) and bright (K < 14 mag) type-1 active galactic nuclei (AGNs) taken with the Infrared Camera on board AKARI. The 2.5-5.0 µm spectral region contains emission lines such as Brβ (2.63 µm), Brα (4.05 µm), and polycyclic aromatic hydrocarbons (3.3 µm), …
Episodic Ejection from Active Asteroid 311P/PANSTARRS
Mutchler, Max; Jewitt, David; Agarwal, Jessica +2 more
We examine the development of the active asteroid 311P/PANSTARRS (formerly, 2013 P5) in the period from 2013 September to 2014 February using high resolution images from the Hubble Space Telescope. This multi-tailed object is characterized by a single, reddish nucleus of absolute magnitude H >= 18.98 ± 0.10, corresponding to an equal-area spher…