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Warm ISM in the Sagittarius A Complex. I. Mid-J CO, atomic carbon, ionized atomic carbon, and ionized nitrogen sub-mm/FIR line observations with the Herschel-HIFI and NANTEN2/SMART telescopes

Stutzki, J.; Güsten, R.; Requena-Torres, M. A. +3 more

Aims: We investigate the spatial and spectral distribution of the local standard of rest (LSR) velocity resolved submillimetre emission from the warm (25-90 K) gas in the Sgr A Complex, located in the Galactic centre.
Methods: We present large-scale submillimetre heterodyne observations towards the Sgr A Complex covering ~300 arcmin^…

Many new variable stars discovered in the core of the globular cluster NGC 6715 (M 54) with EMCCD observations

Surdej, J.; Snodgrass, C.; Horne, K. +39 more

Context. We show the benefits of using electron-multiplying CCDs and the shift-and-add technique as a tool to minimise the effects of atmospheric turbulence, such as blending between stars in crowded fields, and to avoid saturated stars in the fields observed. We intend to complete, or improve on, the census of the variable star population in glob…

X-Ray Afterglow of Swift J1644+57: A Compton Echo?

Cheng, K. S.; Kong, Albert K. H.; Chernyshov, D. O. +2 more

Swift, Chandra, and XMM have found a weak but nearly constant X-ray component from Swift J1644+57 that appeared at ∼500 days and was visible at least until ∼1400 days after the stellar capture, which cannot be explained by standard tidal disruption theories. We suggest that this X-ray afterglow component may result from the Thomson scattering betw…

Multiwavelength study of RX J2015.6+3711: a magnetic cataclysmic variable with a 2-h spin period

Campana, S.; de Martino, D.; Rea, N. +4 more

The X-ray source RX J2015.6+3711 was discovered by ROSAT in 1996 and recently proposed to be a cataclysmic variable (CV). Here, we report on an XMM-Newton observation of RX J2015.6+3711 performed in 2014, where we detected a coherent X-ray modulation at a period of 7196 ± 11 s and discovered other significant (>6σ) small-amplitude periodicities…

Galaxy Infall by Interacting with Its Environment: A Comprehensive Study of 340 Galaxy Clusters

Gandhi, Poshak; Makishima, Kazuo; Nakazawa, Kazuhiro +7 more

To study systematically the evolution of the angular extents of the galaxy, intracluster medium (ICM), and dark matter components in galaxy clusters, we compiled the optical and X-ray properties of a sample of 340 clusters with redshifts <0.5, based on all the available data from the Sloan Digital Sky Survey and Chandra/XMM-Newton. For each clu…

Method for improving line flux and redshift measurements with narrowband filters

Milvang-Jensen, B.; Fynbo, J. P. U.; Nilsson, K. K. +5 more

Context. High redshift star-forming galaxies are discovered routinely because of a flux excess in narrowband filters caused by an emission line. In most cases, the width of such filters is broader than typical line widths, and the throughput of the filters varies substantially within the bandpass. This leads to substantial uncertainties in redshif…

Optical Properties of Amorphous Alumina Dust in the Envelopes around O-Rich AGB Stars

Suh, Kyung-Won

We investigate optical properties of amorphous alumina (Al_2O_3) dust grains in the envelopes around O-rich asymptotic giant branch (AGB) stars considering the laboratory measured optical data. We derive the optical constants of amorphous alumina in a wide wavelength range that satisfy the Kramers-Kronig relation and reproduce the laboratory measu…

The XMM-Newton spectra of the 2012 outburst of the black hole candidate 4U 1630-47 revisited

Méndez, Mariano; Wang, Yanan

Recent XMM-Newton observations of the black hole candidate 4U 1630-47 during the 2012 outburst revealed three relativistically Doppler-shifted emission lines that were interpreted as arising from baryonic matter in the jet of this source. Here, we reanalyse those data and find an alternative model that, with less free parameters than the model wit…

AKARI far-infrared maps of the zodiacal dust bands

Nakagawa, Takao; Doi, Yasuo; Takita, Satoshi +6 more

Zodiacal emission is thermal emission from interplanetary dust. Its contribution to the sky brightness is non-negligible in the region near the ecliptic plane, even in the far-infrared (far-IR) wavelength regime. We analyze zodiacal emission observed by the AKARI far-IR all-sky survey, which covers 97% of the entire sky at arcminute-scale resoluti…

A Phase-Gradient-Autofocus Algorithm for the Recovery of MARSIS Subsurface Data

Picardi, G.; Seu, R.; Restano, M.