11,986 research outputs found
The dust morphology of the elliptical Galaxy M86 with SPIRE
We present Herschel-SPIRE observations at 250â500âÎŒm of the giant elliptical galaxy Mâ86 and examine the distribution of the resolved cold dust emission and its relation with other galactic tracers. The SPIRE images reveal three dust components: emission from the central region; a dust lane extending north-south; and a bright emission feature 10âkpc to the south-east. We estimate that ~10^6âM_â of dust is spatially coincident with atomic and ionized hydrogen, originating from stripped material from the nearby spiral NGC 4438 due to recent tidal interactions with Mâ86. The gas-to-dust ratio of the cold gas component ranges from ~20â80. We discuss the different heating mechanisms for the dust features
SPIRE imaging of Mâ82: Cool dust in the wind and tidal streams
Mâ82 is a unique representative of a whole class of galaxies, starbursts with superwinds, in the Very Nearby Galaxy Survey with Herschel. In addition, its interaction with the Mâ81 group has stripped a significant portion of its interstellar medium from its disk. SPIRE maps now afford better characterization of the far-infrared emission from cool dust outside the disk, and sketch a far more complete picture of its mass distribution and energetics than previously possible. They show emission coincident in projection with the starburst wind and in a large halo, much more extended than the PAH band emission seen with Spitzer. Some complex substructures coincide with the brightest PAH filaments, and others with tidal streams seen in atomic hydrogen. We subtract the far-infrared emission of the starburst and underlying disk from the maps, and derive spatially-resolved far-infrared colors for the wind and halo. We interpret the results in terms of dust mass, dust temperature, and global physical conditions. In particular, we examine variations in the dust physical properties as a function of distance from the center and the wind polar axis, and conclude that more than two thirds of the extraplanar dust has been removed by tidal interaction, and not entrained by the starburst wind
Functional design for operational earth resources ground data processing
The author has identified the following significant results. Study emphasis was on developing a unified concept for the required ground system, capable of handling data from all viable acquisition platforms and sensor groupings envisaged as supporting operational earth survey programs. The platforms considered include both manned and unmanned spacecraft in near earth orbit, and continued use of low and high altitude aircraft. The sensor systems include both imaging and nonimaging devices, operated both passively and actively, from the ultraviolet to the microwave regions of the electromagnetic spectrum
Z-Spec: A MM-Wave Spectrometer For Measuring Redshifts Of Submillimeter Galaxies
We are building a background-limited, broadband millimeter-wave spectrometer (Z-Spec) for observations of CO rotational transitions from high-redshift dusty galaxies. The large instantaneous bandwidth (195 to 310 GHz) will enable redshifts of dust obscured galaxies to be unambiguously measured. Z-Spec uses a waveguide-coupled grating architecture in which the light propagation is confined within a parallel-plate waveguide. The grating is extremely compact compared to a classical free-space system. An array of silicon nitride bolometers cooled to 100 mK will provide background-limited performance. Z-Spec serves as a technology demonstration for a future space-borne far-infrared grating spectrometer
Beta-Hydroxybutyrate Alters the mRNA Cytokine Profile from Mouse Macrophages Challenged with Streptococcus uberis
The objective of this study was to determine if ÎČ-hydroxybutyrate (BHB) altered inflammatory responses in macrophages challenged with a common mastitis pathogen, Streptococcus uberis. Mouse macrophages (RAW 264.7 line) were cultured either in the presence or absence of BHB for 24 h, and then challenged or not with S. uberis. Relative transcript abundance of cell membrane receptors (TLR2 and GPR109a), cytokines (IL-1ÎČ, IL-10, TNFα, and TGFÎČ), and chemokines (CXCL2 and CCL5) were determined using quantitative real-time polymerase chain reaction (qPCR) and normalized against the geometric mean of HPRT and B2M. Streptococcus uberis activated the macrophages, noted by greater transcript abundance of analyzed genes. Intriguingly, S. uberis increased GPR109a mRNA abundance, a receptor that is activated by BHB. Consequently, BHB dose-dependently increased transcript abundance of the pro-inflammatory cytokine (IL-1ÎČ) and the anti-inflammatory cytokine (IL-10) but had no effect on TNFα or TGFÎČ. Moreover, BHB increased mRNA abundance of the chemokines, CXCL2 and CCL5. These data suggest a dysregulated immune response toward S. uberis due to BHB treatment, similar to what is seen in transition dairy cows. Future studies should be conducted in vivo to test the effect of BHB on immune function during an intramammary challenge
The Warm Molecular Gas Around the Cloverleaf Quasar
We present the first broadband lambda = 1 mm spectrum toward the z=2.56
Cloverleaf Quasar, obtained with Z-Spec, a 1-mm grating spectrograph on the
10.4-meter Caltech Submillimeter Observatory. The 190-305 GHz observation band
corresponds to rest-frame 272 to 444 microns, and we measure the dust continuum
as well as all four transitions of carbon monoxide (CO) lying in this range.
The power-law dust emission, F_nu = 14 mJy (nu/240GHz)^3.9 is consistent with
the published continuum measurements. The CO J=6->5, J=8->7, and J=9->8
measurements are the first, and now provide the highest-J CO information in
this source. Our measured CO intensities are very close to the
previously-published interferometric measurements of J=7->6, and we use all
available transitions and our 13CO upper limits to constrain the physical
conditions in the Cloverleaf molecular gas disk. We find a large mass
(2-50x10^9 Msun) of highly-excited gas with thermal pressure nT > 10^6 Kcm^-3.
The ratio of the total CO cooling to the far-IR dust emission exceeds that in
the local dusty galaxies, and we investigate the potential heating sources for
this bulk of warm molecular gas. We conclude that both UV photons and X-rays
likely contribute, and discuss implications for a top-heavy stellar initial
mass function arising in the X-ray-irradiated starburst. Finally we present
tentative identifications of other species in the spectrum, including a
possible detection of the H20 2_0,2->1_1,1 transition at lambda_rest = 303
microns.Comment: ApJ in press, 12 pages in emulateAp
Wroclaw neutrino event generator
A neutrino event generator developed by the Wroclaw Neutrino Group is
described. The physical models included in the generator are discussed and
illustrated with the results of simulations. The considered processes are
quasi-elastic scattering and pion production modelled by combining the
resonance excitation and deep inelastic scattering.Comment: Talk given at 2nd Scandanavian Neutrino Workshop (SNOW 2006),
Stockholm, Sweden, 2-6 May 2006. 3 pages, 6 figure
Targeted Reflection-Waveform Inversion of Experimental Ground-Penetrating Radar Data for Quantification of Oil Spills Under Sea Ice
Rapid spill detection and mapping are needed with increasing levels of oil exploration and production in the Arctic. Previous work has found that ground-penetrating radar (GPR) is effective for qualitative identification of oil spills under, and encapsulated within, sea ice. Quantifying the spill distribution will aid effective spill response. To this end, we have developed a targeted GPR reflection-waveform inversion algorithm to quantify the geometry of oil spills under and within sea ice. With known electric properties of the ice and oil, we have inverted for oil thickness and variations in ice thickness. We have tested the algorithm with data collected during a controlled spill experiment using 500-MHz radar reflection data. The algorithm simultaneously recovered the thickness of a 5-cm-thick oil layer at the base of the ice to within 8% of the control value, estimated the thickness of a 1-cm-thick oil layer encapsulated within the ice to within 30% of the control value, and accurately mapped centimeter-scale variations in ice thickness
A Method to Assess the Organizing Behaviors Used in Physicians\u27 Counseling of Standardized Parents after Newborn Genetic Screening
Well-organized conversation can improve peopleâs ability to comprehend and retain information. As part of a long-term effort to adapt Quality Improvement techniques for communication, we developed an explicit criteria method to assess usage of three organizing behaviors (OBs): âopening behaviorsâ to establish goals; âstructuring behaviorsâ to guide patients through conversation; and âemphasizing behaviorsâ that signal a need for attention. Pairs of abstractors independently reviewed transcripts in a demonstration sample of conversations between physicians and standardized parents after newborn screening identifies carrier status for sickle cell disease. Criteria for at least one OB were identified in 50/84 transcripts (60%), including 27 with at least one opening behavior (32%), 5 with at least one structuring behavior (6%), and 38 with at least one emphasizing behavior (45%). The limited number of OBs raises concern about communication after newborn screening. Assessment and improvement of OB usage may improve understanding and allow parents to more actively participate in health care
A Census of the High-Density Molecular Gas in M82
We present a three-pointing study of the molecular gas in the starburst
nucleus of M82 based on 190 - 307 GHz spectra obtained with Z-Spec at the
Caltech Submillimeter Observatory. We present intensity measurements,
detections and upper limits, for 20 transitions, including several new
detections of CS, HNC, C2H, H2CO, and CH3CCH lines. We combine our measurements
with previously-published measurements at other frequencies for HCN, HNC, CS,
C34S, and HCO+ in a multi-species likelihood analysis constraining gas mass,
density and temperature, and the species' relative abundances. We find some 1.7
- 2.7 x 10^8 M_sun of gas with n_H2 between 1 - 6 x 10^4 cm^-3 and T > 50 K.
While the mass and temperature are comparable to values inferred from mid-J CO
transitions, the thermal pressure is a factor of 10 - 20 greater. The molecular
interstellar medium is largely fragmented and is subject to ultraviolet
irradiation from the star clusters. It is also likely subject to cosmic rays
and mechanical energy input from the supernovae, and is warmer on average than
the molecular gas in the massive star formation regions in the Milky Way. The
typical conditions in the dense gas in M82's central kpc appear unfavorable for
further star formation; if any appreciable stellar populations are currently
forming, they are likely biased against low mass stars, producing a top-heavy
initial mass function.Comment: 15 pages (using emulateapj.cls), 6 figures, Astrophysical Journal, in
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