379 research outputs found
Was 49b: An Overmassive AGN in a Merging Dwarf Galaxy?
We present a combined morphological and X-ray analysis of Was 49, an
isolated, dual AGN system notable for the presence of a dominant AGN Was 49b in
the disk of the primary galaxy Was 49a, at a projected radial distance of 8 kpc
from the nucleus. Using X-ray data from Chandra, NuSTAR, and Swift, we find
that this AGN has a bolometric luminosity of L_bol ~ 2 x 10^45 erg/s, with a
black hole mass of M_BH=1.3^{+2.9}_{-0.9} x 10^8 M_Sol. Despite its large mass,
our analysis of optical data from the Discovery Channel Telescope shows that
the supermassive black hole is hosted by a stellar counterpart with a mass of
only 5.6^{+4.9}_{-2.6} x 10^9 M_Sol, making the SMBH potentially larger than
expected from SMBH-galaxy scaling relations, and the stellar counterpart
exhibits a morphology that is consistent with dwarf elliptical galaxies. Our
analysis of the system in the r and K bands indicates that Was 49 is a minor
merger, with a mass ratio of Was 49a to Was 49b between 1:7 and 1:15. This is
in contrast with findings that the most luminous merger-triggered AGNs are
found in major mergers, and that minor mergers predominantly enhance AGN
activity in the primary galaxy.Comment: 11 pages, 6 figures, accepted for publication in Ap
Prehistory In The Calamity Creek Valley Brewster County, Texas
Th e fi ndings of a May 28–July 2, 1996, summer archaeological fi eld school conducted by the Center for Big Bend Studies, Sul Ross State University, in cooperation with the Texas Parks and Wildlife Department, are reported herein. Th e focus of the fi eld school was on a 335-acre segment of the Calamity Creek valley within Elephant Mountain Wildlife Management Area in Brewster County, Texas. Twelve archaeological sites, 41BS37, 41BS764, 41BS810, 41BS811, 41BS814, 41BS1104, 41BS1480, 41BS1481, 41BS1482, 41BS1483, 41BS1484, and 41BS1485—six of which were previously identifi ed—were instrument-mapped, subjected to controlled surface-collecting, and limited subsurface testing. All excavation was directed towards intrasite cultural features exposed and threatened by sheet erosion and/or cutbank sloughing. Evidence for largely transitory Late Paleoindian through Contact period occupation of the creek valley was recovered. Based on all gathered data, the narrow Calamity Creek basin is likely to have served in prehistory as a resource-rich north-south corridor through which small bands of hunter-gatherers passed at frequent intervals between two major physiographic zones. Artifacts and special samples recovered as a result of this project are curated at Texas Parks and Wildlife facilities in Austin, Texas
Neutrophil and lymphocyte response to vitamins C and E supplementation in young calves
Calves were bottle-fed milk replacers at 10% of weekly adjusted body weight for 8 wk. Treatments were 1) no supplements (control), 2) .16 oz vitamin C, or 3) .16 oz vitamin C plus 125 IU/lb vitamin E. Lymphocytes and neutrophils isolated from day 14 and day 28 blood samples were assayed for neutrophil-mediated S. aureus phagocytosis and antibody-dependent cellular cytotoxicity, and for mitogen induced lymphocyte proliferation. Eye and nasal discharges of calves supplemented with vitamin C and vitamins C plus E were less than those of control calves for wk 1 to 8. Lymphocyte proliferation with the mitogens showed a trend for higher responses at wk 2 in vitamin C plus E supplemented calves. Neutrophils of calves supplemented with vitamin C showed decreased phagocytosis and lysis functions compared to those of control calves at wk 2 and 4. Neutrophil function of calves supplemented with vitamins C plus E was near or slightly higher than that of controls at wk 2 and 4, suggesting that the addition of vitamin E negated the adverse effects that vitamin C alone had on neutrophil functions.; Dairy Day, 1989, Kansas State University, Manhattan, KS, 1989; The 1989 Annual KSU Dairy Day is known as Dairy Day, 198
External iliac artery dissection secondary to endofibrosis in a cyclist
Endofibrosis of the external iliac artery is an uncommon disease affecting primarily young, otherwise healthy, endurance athletes. Thigh pain during maximal exercise with quick resolution postexercise is characteristic of the so-called cyclist's iliac syndrome. We report an unusual case in which the typical endofibrotic plaque was accompanied by dissection of the external iliac artery. The patient was treated surgically with excision of the affected artery segment and placement of an interposition graft. This case highlights an unusual finding in association with external iliac artery endofibrosis and provides an opportunity to briefly review the literature on the subject
Buried AGNs in Advanced Mergers:Mid-infrared color selection as a dual AGN finder
A direct consequence of hierarchical galaxy formation is the existence of
dual supermassive black holes (SMBHs), which may be preferentially triggered as
active galactic nuclei (AGN) during galaxy mergers. Despite decades of
searching, however, dual AGNs are extremely rare, and most have been discovered
serendipitously. Using the all-sky WISE survey, we identified a population of
over 100 morphologically identified interacting galaxies or mergers that
display red mid-infrared colors often associated in extragalactic sources with
powerful AGNs. The vast majority of these advanced mergers are optically
classified as star-forming galaxies suggesting that they may represent an
obscured population of AGNs that cannot be found through optical studies. In
this work, we present Chandra/ACIS observations and near-infrared spectra with
the Large Binocular Telescope of six advanced mergers with projected pair
separations less than ~ 10 kpc. The combined X-ray, near-infrared, and
mid-infrared properties of these mergers provide confirmation that four out of
the six mergers host at least one AGN, with four of the mergers possibly
hosting dual AGNs with projected separations less than ~10 kpc, despite showing
no firm evidence for AGNs based on optical spectroscopic studies. Our results
demonstrate that 1) optical studies miss a significant fraction of single and
dual AGNs in advanced mergers, and 2) mid-infrared pre-selection is extremely
effective in identifying dual AGN candidates in late-stage mergers. Our
multi-wavelength observations suggest that the buried AGNs in these mergers are
highly absorbed, with intrinsic column densities in excess of N_H >10^24cm^-2,
consistent with hydrodynamic simulations.Comment: 23 pages, 11 figures, accepted for publication to Ap
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