5,832 research outputs found
Lyman-alpha Imaging of a Very Luminous z=2.3 Starburst Galaxy with WFPC2
We investigate a very luminous Lyman-alpha emitting galaxy, associated with a
z=2.3 damped absorption system in the spectrum of the QSO PHL 957. The galaxy
was observed with the HST WFPC2, through a narrow filter (F410M) corresponding
to rest-frame Lyman -alpha, for 41.2 ksec, with shorter exposures in F555W and
F814W. The galaxy is resolved into a close (0.35 arcsec) pair of two
components, CFgA and CFgB. The profile of CFgA is consistent with an
exponential disk, but CFgB is closer to a bulge galaxy. Fr om the observed
colours we estimate rest-frame Lyman-alpha equivalent widths of 151 Angstroms
for CFgA and 33 for CFgB. From the F814W and F555W magnitudes we estimate
rest-frame blue-band absolute magnitudes of -23.12 for CFgA and -23.24 for
CFgB, signi ficantly brighter than local galaxies of the same size. CFgA shows
a remarkable 3.9 magnitudes of surface brightness enhancement relative to local
spirals, and we speculate that this may be the result of a very luminous
starburst, triggered by the merger of the two components. The Lyman-alpha
emission could be from a brief phase early in the starburst in which most of
these photons can escape.
We search for other z=2.3 galaxies with strong Lyman-alpha emission,
selecting these by a colour F410M-F555W<-0.2. Eight candidate sources, all
fainter than CFgA, are identified. One is a point-source and may be an AGN; the
others are irregular a nd of low surface brightness, appearing typical of Lyman
break galaxies, but with Lyman-alpha equivalent widths near 100 Angstroms.Comment: 17 pages, Latex, 17 figures. Accepted for publication in MNRA
Recent advances in coherent optics. Filtering of spatial frequencies, holography
Applications of coherent light in areas of spatial filtering and holograph
The Morphology of 9 Radio-selected Faint Galaxies from deep HST Imaging
Using the HST WFPC2 we perform deep I-band imaging of 9 radio-selected (limit
14 microJanskys at 8.5 GHz) faint galaxies from Roche, Lowenthal and Koo
(2002). Two are also observed in V. Six of the galaxies have known redshifs of
0.4<z<1.0. Radial intensity profiles indicate that 7 are disk galaxies and 2
are bulge-dominated. Four of the six with redshifts have a high optical surface
brightness compared to typical disk galaxies. Two of the 9 galaxies are in
close interacting pairs, another two are very asymmetric and three have large,
luminous rings resembling the collisional starburst rings in the Cartwheel
galaxy. In most of these galaxies the high radio luminosities are probably the
result of interaction-triggered starbursts. The mixture of observed
morphologies suggests that enhanced radio luminosities often persist for >0.2
Gyr, to a late stage of the interaction. One of these 9 galaxies may be an
exception in that it is a large red elliptical and its strong radio emission is
more likely to be from an obscured AGN.Comment: 12 pages, latex, 8 figures, accepted for publication in MNRA
Robotic mobile servicing platform for space station
The semi-autonomous inspection and servicing of the Space Station's major thermal, electrical, mechanical subsystems are critical needs for the safe and reliable operation of the station. A conceptual design is presented of a self-intelligent, small and highly mobile robotic platform. Equipped with suitable inspection sensors (cameras, ammonia detectors, etc.), this system's primary mission is to perform routine, autonomous inspection of the Station's primary subsystems. Typical tasks include detection of leaks from thermal fluid or refueling lines, as well as detection of micro-meteroid damage to the primary structure. Equipped with stereo cameras and a dexterous manipulator, simple teleoperator repairs and small On-orbit Replacement Unit (ORU) changeout can also be accomplished. More difficult robotic repairs would be left to the larger, more sophisticated Mobile Remote Manipulator System (MRMS). An ancillary function is to ferry crew members and equipment around the station. The primary design objectives were to provide a flexible, but uncomplicated robotic platform, one which caused minimal impact to the design of the Station's primary structure but could accept more advanced telerobotic technology as it evolves
Color Magnitude Relation and Morphology of Low-Redshift ULIRGs in SDSS
We present color-magnitude and morphological analysis of 54 low-redshift
ULIRGs, a subset of the IRAS 1Jy sample (Kim & Sanders, 1998), in the SDSS. The
ULIRGs are on average 1 magnitude brighter in M0.1r than the SDSS galaxies
within the same redshift range. The majority of the ULIRGs (~87%) have the
colors typical of the blue cloud, and only 4 sources (~7%) are located in the
red sequence. While ULIRGs are popularly thought to be precursors to a QSO
phase, we find few (~6%) in the "green valley" where the majority of the X-ray
and IR selected AGNs are found, and none of which harbors an AGN. For the 14
previously spectroscopic identified AGNs (~28%), we perform PSF subtractions
and find that on average the central point sources contribute less than one
third to the total luminosity, and that their high optical luminosities and
overall blue colors are apparently the result of star formation activity of the
host galaxies. Visual inspection of the SDSS images reveals a wide range of
disturbed morphologies. A detailed morphology analysis using Gini and M20
coefficients shows that slightly less than one half (~42% in g band) of the
ULIRGs are located in the region where most local mergers are found. The
heterogeneous distribution of ULIRGs in the G-M20 space is qualitatively
consistent with the results found by numerical simulations of disk-disk
mergers. Our study also shows that the measured morphological parameters are
systematically affected by the SNR and thus the merging galaxies can appear at
various regions in the G-M20 space. In general, our results reinforce the view
that ULIRGs contain young stellar populations and are mergers in progress. Our
study provides a uniform comparison sample for studying ULIRGs at higher
redshifts such as Spitzer mid-IR selected ULIRGs at z=1~2 and submm galaxies.Comment: 42 pages, 11 figures, ApJ accepte
Artist in Residence
Program listing performers and works performe
The Controversy Over Generic Equivalency of Drugs
The truth about generic equivalency has not yet been determined. The arguments in the generic equivalency controversy are confounded by names, proprietary (trademark, brand name) as opposed to non-proprietary (generic, branded-generic), yet quality of the products is not necessarily related to any name. The efficacy and not the name of the product is important. The crucial question to ask is whether the product is clinically or therapeutically effective, giving reliable and uniform results
Overview of the CSIRO Australian Animal Health Laboratory
SummaryEmerging infectious diseases arising from livestock and wildlife pose serious threats to global human health, as shown by a series of continuous outbreaks involving highly pathogenic influenza, SARS, Ebola and MERS. The risk of pandemics and bioterrorism threats is ever present and growing, but our ability to combat them is limited by the lack of available vaccines, therapeutics and rapid diagnostics. The use of high bio-containment facilities, such as the CSIRO Australian Animal Health Laboratory, plays a key role studying these dangerous pathogens and facilitates the development of countermeasures. To combat diseases like MERS, we must take a holistic approach that involves the development of early biomarkers of infection, a suite of treatment options (vaccines, anti-viral drugs and antibody therapeutics) and appropriate animal models to test the safety and efficacy of candidate treatments
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