ﻻ يوجد ملخص باللغة العربية
We study the edge-on galaxy NGC 5775, utilizing a 58.2 ks {sl Chandra} ACIS-S observation together with complementary {sl HST} ACS, {sl Spitzer} IRAC and other multi-wavelength data sets. This edge-on galaxy, with its disk-wide active star formation, is particularly well-suited for studying the disk/halo interaction on sub-galactic scales. We detect 27 discrete X-ray sources within the $D_{25}$ region of the galaxy, including an ultra-luminous source with a 0.3-7 keV luminosity of $sim7times10^{40}rm ergs s^{-1}$. The source-removed diffuse X-ray emission shows several prominent extraplanar features, including a $sim10rm kpc$ diameter ``shell-like feature and a ``blob reaching a projected distance of $sim25rm kpc$ from the galactic disk. The bulk of the X-ray emission in the halo has a scale height of $sim$1.5 kpc and can be characterized by a two-temperature optically thin thermal plasma with temperatures of $sim$ 0.2 and 0.6 keV and a total 0.3-2 keV luminosity of $sim3.5times10^{39}rm ergs s^{-1}$. The high-resolution, multi-wavelength data reveal the presence of several extraplanar features around the disk, which appear to be associated with the in-disk star formation. We suggest that hot gas produced with different levels of mass loading can have different temperatures, which may explain the characteristic temperatures of hot gas in the halo. We have obtained a sub-galactic scale X-ray-intensity-star formation relation, which is consistent with the integrated version in other star forming galaxies.
Cosmic rays play a pivotal role in launching galactic winds, particularly in quiescently star-forming galaxies where the hot gas alone is not sufficient to drive a wind. Except for the Milky Way, not much is known about the transport of cosmic rays i
We present the analysis of the XMM-Newton data of the Circum-Galactic Medium of MASsive Spirals (CGM-MASS) sample of six extremely massive spiral galaxies in the local Universe. All the CGM-MASS galaxies have diffuse X-ray emission from hot gas detec
A halo model with heavy relic neutrinos N belonging to a fourth generation and their annihilations in galactic halo may explain the recent evidence of diffused gamma (GeV) radiation around galactic plane. We considered a neutrino mass in the narrow r
X-ray-emitting coronae of nearby galaxies are expected to be produced either by accretion from the intergalactic medium and/or by various galactic feedback. We herein present a systematical analysis of the Chandra observations of 53 nearby edge-on di
Galaxies are surrounded by halos of hot gas whose mass and origin remain unknown. One of the most challenging properties to measure is the metallicity, which constrains both of these. We present a measurement of the metallicity around NGC 891, a near