30 research outputs found
Exploring the dust content of galactic haloes with Herschel - IV. NGC 3079
We present the results from an analysis of deep Herschel far-infrared (far-IR) observations of the edge-on disc galaxy NGC 3079. The point spread function-cleaned Photodetector Array Camera and Spectrometer (PACS) images at 100 and 160 ÎŒm display a 25 Ă 25 kpc2 X-shape structure centred on the nucleus that is similar in extent and orientation to that seen in H α, X-rays, and the far-ultraviolet. One of the dusty filaments making up this structure is detected in the Spectral and Photometric Imaging Receiver 250 ÎŒm map out to âŒ25 kpc from the nucleus. The match between the far-IR filaments and those detected at other wavelengths suggests that the dusty material has been lifted out of the disc by the same large-scale galactic wind that has produced the other structures in this object. A closer look at the central 10 Ă 10 kpc2 region provides additional support for this scenario. The dust temperatures traced by the 100-160 ÎŒm flux ratios in this region are enhanced within a biconical region centred on the active galactic nucleus, aligned along the minor axis of the galaxy, and coincident with the well-known double-lobed cm-wave radio structure and H α-X-ray nuclear superbubbles. PACS imaging spectroscopy of the inner 6 kpc region reveals broad [C ii] 158 ÎŒm emission line profiles and OH 79 ÎŒm absorption features along the minor axis of the galaxy with widths well in excess of those expected from beam smearing of the disc rotational motion. This provides compelling evidence that the cool material traced by the [C ii] and OH features directly interacts with the nuclear ionized and relativistic outflows traced by the H α, X-ray, and radio emission
Canine papillomatosis: a retrospective study of 24 cases (2001-2011) and immunohistochemical characterization
Prospects for Studies of Stellar Evolution and Stellar Death in the JWST Era
I review the prospects for studies of the advanced evolutionary stages of
low-, intermediate- and high-mass stars by the JWST and concurrent facilities,
with particular emphasis on how they may help elucidate the dominant
contributors to the interstellar dust component of galaxies. Observations
extending from the mid-infrared to the submillimeter can help quantify the
heavy element and dust species inputs to galaxies from AGB stars. JWST's MIRI
mid-infrared instrument will be so sensitive that observations of the dust
emission from individual intergalactic AGB stars and planetary nebulae in the
Virgo Cluster will be feasible. The Herschel Space Observatory will enable the
last largely unexplored spectral region, the far-IR to the submillimeter, to be
surveyed for new lines and dust features, while SOFIA will cover the wavelength
gap between JWST and Herschel, a spectral region containing important fine
structure lines, together with key water-ice and crystalline silicate bands.
Spitzer has significantly increased the number of Type II supernovae that have
been surveyed for early-epoch dust formation but reliable quantification of the
dust contributions from massive star supernovae of Type II, Type Ib and Type Ic
to low- and high-redshift galaxies should come from JWST MIRI observations,
which will be able to probe a volume over 1000 times larger than Spitzer.Comment: 24 pages, 19 figures. To appear in `Astrophysics in the Next Decade:
JWST and Concurrent Facilities' (JWST Conference Proceedings), edited by H.
A. Thronson, M. Stiavelli and A. G. G. M. Tielens; Springer Series:
Astrophysics and Space Science Proceeding
Cold Gas in Cluster Cores
I review the literature's census of the cold gas in clusters of galaxies.
Cold gas here is defined as the gas that is cooler than X-ray emitting
temperatures (~10^7 K) and is not in stars. I present new Spitzer IRAC and MIPS
observations of Abell 2597 (PI: Sparks) that reveal significant amounts of warm
dust and star formation at the level of 5 solar masses per year. This rate is
inconsistent with the mass cooling rate of 20 +/- 5 solar masses per year
inferred from a FUSE [OVI] detection.Comment: 10 pages, conference proceeding
Operations management teaching on European MBA programmes
A comprehensive review of the literature established that several investigations
have been made of operations management teaching in the USA, whereas almost
nothing has been published on European teaching. Therefore, an exploratory
investigation was made of operations management teaching on the MBA courses of
ten leading European business schools. The results show that course content is
similar across schools, but there are large variations on three dimensions: the
time allocated by schools to the subject; the balance between operations
strategy and tools and techniques in teaching; and the level of emphasis given
to service operations. The results also indicate the emerging importance of
integrating operations management with other subjects in the MBA curriculum and
the key challenge facing faculty - the need to raise the perceived importance of
operations management. The comparison of courses will be of interest to all
operations management faculty who teach core courses and particularly those who
are looking for ideas on how to re-design courses
Exploring the dust content of galactic haloes with Herschel - IV. NGC 3079
We present the results from an analysis of deep Herschel far-infrared (far-IR) observations of the edge-on disc galaxy NGC 3079. The point spread function-cleaned Photodetector Array Camera and Spectrometer (PACS) images at 100 and 160 ÎŒm display a 25 Ă 25 kpc2 X-shape structure centred on the nucleus that is similar in extent and orientation to that seen in H α, X-rays, and the far-ultraviolet. One of the dusty filaments making up this structure is detected in the Spectral and Photometric Imaging Receiver 250 ÎŒm map out to âŒ25 kpc from the nucleus. The match between the far-IR filaments and those detected at other wavelengths suggests that the dusty material has been lifted out of the disc by the same large-scale galactic wind that has produced the other structures in this object. A closer look at the central 10 Ă 10 kpc2 region provides additional support for this scenario. The dust temperatures traced by the 100-160 ÎŒm flux ratios in this region are enhanced within a biconical region centred on the active galactic nucleus, aligned along the minor axis of the galaxy, and coincident with the well-known double-lobed cm-wave radio structure and H α-X-ray nuclear superbubbles. PACS imaging spectroscopy of the inner 6 kpc region reveals broad [C ii] 158 ÎŒm emission line profiles and OH 79 ÎŒm absorption features along the minor axis of the galaxy with widths well in excess of those expected from beam smearing of the disc rotational motion. This provides compelling evidence that the cool material traced by the [C ii] and OH features directly interacts with the nuclear ionized and relativistic outflows traced by the H α, X-ray, and radio emission. © 2021 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society.Immediate accessThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]
An Infrared Survey of Brightest Cluster Galaxies. II. Why are Some Brightest Cluster Galaxies Forming Stars?
Quillen et al. presented an imaging survey with the Spitzer Space Telescope of 62 brightest cluster galaxies with optical line emission located in the cores of X-ray-luminous clusters. They found that at least half of these sources have signs of excess IR emission. Here we discuss the nature of the IR emission and its implications for cool core clusters. The strength of the mid-IR excess emission correlates with the luminosity of the optical emission lines. Excluding the four systems dominated by an AGN, the excess mid-IR emission in the remaining brightest cluster galaxies is likely related to star formation. The mass of molecular gas (estimated from CO observations) is correlated with the IR luminosity as found for normal star-forming galaxies. The gas depletion timescale is about 1 Gyr. The physical extent of the IR excess is consistent with that of the optical emission-line nebulae. This supports the hypothesis that star formation occurs in molecular gas associated with the emission-line nebulae and with evidence that the emission-line nebulae are mainly powered by ongoing star formation. We find a correlation between mass deposition rates () estimated from the X-ray emission and the star formation rates estimated from the IR luminosity. The star formation rates are 1/10 to 1/100 of the mass deposition rates, suggesting that the reheating of the intracluster medium is generally very effective in reducing the amount of mass cooling from the hot phase but not eliminating it completely