9 research outputs found
Discovery of a low-luminosity spiral DRAGN
Standard galaxy formation models predict that large-scale double-lobed radio
sources, known as DRAGNs, will always be hosted by elliptical galaxies. In
spite of this, in recent years a small number of spiral galaxies have also been
found to host such sources. These so-called spiral DRAGNs are still extremely
rare, with only cases being widely accepted. Here we report on the
serendipitous discovery of a new spiral DRAGN in data from the Giant Metrewave
Radio Telescope (GMRT) at 322 MHz. The host galaxy, MCG+07-47-10, is a face-on
late-type Sbc galaxy with distinctive spiral arms and prominent bulge
suggesting a high black hole mass. Using WISE infra-red and GALEX UV data we
show that this galaxy has a star formation rate of 0.16-0.75
Myr, and that the radio luminosity is dominated by
star-formation. We demonstrate that this spiral DRAGN has similar environmental
properties to others of this class, but has a comparatively low radio
luminosity of = 1.1210 W Hz, two orders
of magnitude smaller than other known spiral DRAGNs. We suggest that this may
indicate the existence of a previously unknown low-luminosity population of
spiral DRAGNS.Comment: 4 pages, Accepted for publication in Astronomy and Astrophysic
Associated molecular and atomic clouds with X-ray shell of superbubble 30 Doradus C in the LMC
30 Doradus C is a superbubble which emits the brightest nonthermal X- and TeV
gamma-rays in the Local Group. In order to explore detailed connection between
the high energy radiation and the interstellar medium, we have carried out new
CO and HI observations using the Atacama Large MillimeterSubmillimeter Array
(ALMA), Atacama Submillimeter Telescope Experiment, and the Australia Telescope
Compact Array with resolutions of up to 3 pc. The ALMA data of CO( =
1-0) emission revealed 23 molecular clouds with the typical diameters of
6-12 pc and masses of 600-10000 . The comparison with
the X-rays of - at 3 pc resolution shows that X-rays are
enhanced toward these clouds. The CO data were combined with the HI to estimate
the total interstellar protons. Comparison of the interstellar proton column
density and the X-rays revealed that the X-rays are enhanced with the total
proton. These are most likely due to the shock-cloud interaction modeled by the
magnetohydrodynamical simulations (Inoue et al. 2012, ApJ, 744, 71). Further,
we note a trend that the X-ray photon index varies with distance from the
center of the high-mass star cluster, suggesting that the cosmic-ray electrons
are accelerated by one or multiple supernovae in the cluster. Based on these
results we discuss the role of the interstellar medium in cosmic-ray particle
acceleration.Comment: 20 pages, 14 figures, 3 tables, accepted for publication in The
Astrophysical Journa
Dios: The Dark Baryon Exploring Mission
DIOS (Diffuse Intergalactic Oxygen Surveyor) is a small satellite aiming for a launch around 2022 with JAXA's Epsilon rocket. Its main aim is a search for warm-hot intergalactic medium with high-resolution X-ray spectroscopy of redshifted emission lines from OVII and OVIII ions. The superior energy resolution of TES microcalorimeters combined with a wide field of view (30 diameter) will enable us to look into gas dynamics of cosmic plasmas in a wide range of spatial scales from Earths magnetosphere to unvirialized regions of clusters of galaxies. Mechanical and thermal design of the spacecraft and development of the TES calorimeter system are described. Employing an enlarged X-ray telescope with a focal length of 1.2 m and fast repointing capability, DIOS can observe absorption features from X-ray afterglows of distant gamma-ray bursts
Discovery of molecular and atomic clouds associated with the Magellanic superbubble 30 Doradus C
We analyzed the 2.6 mm CO and 21 cm H i lines toward the Magellanic superbubble 30 Doradus C, in order to reveal the associated molecular and atomic gas. We uncovered five molecular clouds in a velocity range from 251 to 276 km s⁻¹ toward the western shell. The non-thermal X-rays are clearly enhanced around the molecular clouds on a parsec scale, suggesting possible evidence for magnetic field amplification via shock–cloud interaction. The thermal X-rays are brighter in the eastern shell, where there are no dense molecular or atomic clouds, opposite to the western shell. The TeV γ-ray distribution may spatially match the total interstellar proton column density as well as the non-thermal X-rays. If the hadronic γ-ray is dominant, the total energy of the cosmic-ray protons is at least ∼1.2 × 10⁵⁰ erg with the estimated mean interstellar proton density ~60 cm⁻³. In addition, the γ-ray flux associated with the molecular cloud (e.g., MC3) could be detected and resolved by the Cherenkov Telescope Array (CTA). This should permit CTA to probe the diffusion of cosmic-rays into the associated dense ISM.H. Sano, Y. Yamane, F. Voisin, K. Fujii, S. Yoshiike, T. Inaba, K. Tsuge, Y. Babazaki, I. Mitsuishi, R. Yang, F. Aharonian, G. Rowell, M.D. Filipović, N. Mizuno, K. Tachihara, A. Kawamura, T. Onishi, and Y. Fuku