9,471 research outputs found
Clustering in Deep (Submillimeter) Surveys
Hughes & Gaztanaga (2001, see article in these proceedings) have presented
realistic simulations to address key issues confronting existing and
forthcoming submm surveys. An important aspect illustrated by the simulations
is the effect induced on the counts by the sampling variance of the large-scale
galaxy clustering. We find factors of up to 2-4 variation (from the mean) in
the extracted counts from deep surveys identical in area (6 sqr arcmin) to the
SCUBA surveys of the Hubble Deep Fields (HDF). Here we present a recipe to
model the expected degree of clustering as a function of sample area and
redshift.Comment: 5 pages, 1 figure, UMass/INAOE conference proceedings on `Deep
millimeter surveys', eds. J. Lowenthal and D. Hughes, World Scientifi
Optical off-nuclear spectra of quasar hosts and radio galaxies
We present optical (~3200A to ~9000A) off-nuclear spectra of 26 powerful
active galaxies in the redshift range 0.1 < z < 0.3, obtained with the Mayall
and William Herschel 4-meter class telescopes. The sample consists of
radio-quiet quasars, radio-loud quasars (all with -23 > M_V > -26) and radio
galaxies of Fanaroff & Riley Type II (with extended radio luminosities and
spectral indices comparable to those of the radio-loud quasars). The spectra
were all taken approximately 5 arcseconds off-nucleus, with offsets carefully
selected so as to maximise the amount of galaxy light falling into the slit,
whilst simultaneously minimising the amount of scattered nuclear light. The
majority of the resulting spectra appear to be dominated by the integrated
stellar continuum of the underlying galaxies rather than by light from the
non-stellar processes occurring in the active nuclei, and in many cases a 4000A
break feature can be identified. The individual spectra are described in
detail, and the importance of the various spectral components is discussed.
Stellar population synthesis modelling of the spectra will follow in a
subsequent paper (Nolan et al. 2000).Comment: 23 pages, LaTeX, uses MNRAS style file, incorporates 71 postscript
figures, to be published in MNRAS. Contact author: [email protected]
The ages of quasar host galaxies
We present the results of fitting deep off-nuclear optical spectroscopy of
radio-quiet quasars, radio-loud quasars and radio galaxies at z ~ 0.2 with
evolutionary synthesis models of galaxy evolution. Our aim was to determine the
age of the dynamically dominant stellar populations in the hos t galaxies of
these three classes of powerful AGN. Some of our spectra display residual
nuclear contamination at the shortest wavelengths, but the detailed quality of
the fits longward of the 4000A break provide unequivocal proof, if further
proof were needed, that quasars lie in massive galaxies with (at least at z ~
0.2) evolved stellar populations. By fitting a two-component model we have
separated the very blue (starburst and/or AGN contamination) from the redder
underlying spectral energy distribution, and find that the hosts of all three
classes of AGN are dominated by old stars of age 8 - 14 Gyr. If the blue
component is attributed to young stars, we find that, at most, 1% of the
baryonic mass of these galaxies is involved in star-formation activity at the
epoch of observation. These results strongly support the conclusion reached by
McLure et al. (1999) that the host galaxies of luminous quasars are massive
ellipticals which formed prior to the peak epoch of quasar activity at z ~ 2.5.Comment: 24 pages, LaTeX, uses MNRAS style file, incorporates 19 postscript
figures, final version, to be published in MNRA
A new genus to accommodate \u3cem\u3eGymnopus acervatus\u3c/em\u3e (Agaricales)
Phylogenies based on ITS and LSU nrDNA sequences show Agaricus (Gymnopus) acervatus as unique within the Gymnopus/Rhodocollybia complex. These phylogenies imply that a separate genus is necessary, and Connopus is proposed. Infraspecific morphological and DNA-based variation within C. acervatus suggests that a western North American clade might be reproductively isolated from the eastern North American/Scandinavian clade and that in this species complex the European and eastern North American clade might be conspecific. A Scandinavian exemplar is selected for bar-coding. Two GenBank sequences with name-phylogenetic placement inconsistencies are identified
The Infrared Properties of Submillimeter Galaxies: Clues From Ultra-Deep 70 Micron Imaging
We present 70 micron properties of submillimeter galaxies (SMGs) in the Great
Observatories Origins Deep Survey (GOODS) North field. Out of thirty
submillimeter galaxies (S_850 > 2 mJy) in the central GOODS-N region, we find
two with secure 70 micron detections. These are the first 70 micron detections
of SMGs. One of the matched SMGs is at z ~ 0.5 and has S_70/S_850 and S_70/S_24
ratios consistent with a cool galaxy. The second SMG (z = 1.2) has
infrared-submm colors which indicate it is more actively forming stars. We
examine the average 70 micron properties of the SMGs by performing a stacking
analysis, which also allows us to estimate that S_850 > 2 mJy SMGs contribute 9
+- 3% of the 70 micron background light. The S_850/S_70 colors of the SMG
population as a whole is best fit by cool galaxies, and because of the
redshifting effects these constraints are mainly on the lower z sub-sample. We
fit Spectral Energy Distributions (SEDs) to the far-infrared data points of the
two detected SMGs and the average low redshift SMG (z_{median}= 1.4). We find
that the average low-z SMG has a cooler dust temperature than local
ultraluminous infrared galaxies (ULIRGs) of similar luminosity and an SED which
is best fit by scaled up versions of normal spiral galaxies. The average low-z
SMG is found to have a typical dust temperature T = 21 -- 33 K and infrared
luminosity L_{8-1000 micron} = 8.0 \times 10^11 L_sun. We estimate the AGN
contribution to the total infrared luminosity of low-z SMGs is less than 23%.Comment: Accepted by ApJ. 14 pages, 6 figures. Minor revisions 20th Dec 200
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Incidence, outcomes, and risk factors of pleural effusion in patients receiving dasatinib therapy for Philadelphia chromosome-positive leukemia.
Dasatinib, a second-generation BCR-ABL1 tyrosine kinase inhibitor, is approved for the treatment of chronic myeloid leukemia and Philadelphia chromosome-positive acute lymphoblastic leukemia, both as first-line therapy and after imatinib intolerance or resistance. While generally well tolerated, dasatinib has been associated with a higher risk for pleural effusions. Frequency, risk factors, and outcomes associated with pleural effusion were assessed in two phase 3 trials (DASISION and 034/Dose-optimization) and a pooled population of 11 trials that evaluated patients with chronic myeloid leukemia and Philadelphia chromosome-positive acute lymphoblastic leukemia treated with dasatinib (including DASISION and 034/Dose-optimization). In this largest assessment of patients across the dasatinib clinical trial program (N=2712), pleural effusion developed in 6-9% of patients at risk annually in DASISION, and in 5-15% of patients at risk annually in 034/Dose-optimization. With a minimum follow up of 5 and 7 years, drug-related pleural effusion occurred in 28% of patients in DASISION and in 33% of patients in 034/Dose-optimization, respectively. A significant risk factor identified for developing pleural effusion by a multivariate analysis was age. We found that overall responses to dasatinib, progression-free survival, and overall survival were similar in patients who developed pleural effusion and in patients who did not. clinicaltrials.gov identifier 00481247; 00123474
Constraints on the Accuracy of Photometric Redshifts Derived from BLAST and Herschel/SPIRE Sub-mm Surveys
More than 150 galaxies have been detected in blank-field millimetre and
sub-millimetre surveys. However the redshift distribution of sub-mm galaxies
remains uncertain due to the difficulty in identifying their optical-IR
counterparts, and subsequently obtaining their spectroscopic emission-line
redshifts. In this paper we discuss results from a Monte-Carlo analysis of the
accuracy with which one can determine redshifts from photometric measurements
at sub-millimetre-FIR wavelengths. The analysis takes into account the
dispersion in colours introduced by including galaxies with a distribution of
SEDs, and by including photometric and absolute calibration errors associated
with real observations. We present examples of the probability distribution of
redshifts for individual galaxies detected in the future BLAST and
Herschel/SPIRE surveys. We show that the combination of BLAST and 850um
observations constrain the photometric redshifts with sufficient accuracy to
pursue a program of spectroscopic follow-up with the 100m GBT.Comment: 3 pages, 5 figures, in 2K1BC symposium "Experimental Cosmology at
Millimetre Wavelengths", ed. M. de Petris and M. Gervasi, AIP, in pres
Confirmation of the effectiveness of sub-mm source redshift estimation based on rest-frame radio to FIR photometry
We present a comparison between the published optical, IR and CO
spectroscopic redshifts of 15 (sub-)mm galaxies and their photometric redshifts
as derived from long-wavelength (radio-mm-FIR) photometric data. The redshift
accuracy measured for 12 sub-mm galaxies with at least one robustly-determined
colour in the radio-mm-FIR regime is dz=0.30 (r.m.s.). Despite the wide range
of spectral energy distributions in the local galaxies that are used in an
un-biased manner as templates, this analysis demonstrates that photometric
redshifts can be efficiently derived for sub-mm galaxies with a precision of dz
< 0.5 using only the rest-frame FIR to radio wavelength data.Comment: submitted to MNRAS (1 object removed from analysis, shortening of
paper
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