6 research outputs found
IR and UV Galaxies at z=0.6 -- Evolution of Dust Attenuation and Stellar Mass as Revealed by SWIRE and GALEX
We study dust attenuation and stellar mass of star-forming
galaxies using new SWIRE observations in IR and GALEX observations in UV. Two
samples are selected from the SWIRE and GALEX source catalogs in the
SWIRE/GALEX field ELAIS-N1-00 ( deg). The UV selected sample
has 600 galaxies with photometric redshift (hereafter photo-z) and NUV (corresponding to \rm L_{FUV} \geq 10^{9.6} L_\sun).
The IR selected sample contains 430 galaxies with mJy
(\rm L_{dust} \geq 10^{10.8} L_\sun) in the same photo-z range. It is found
that the mean ratios of the z=0.6 UV galaxies are
consistent with that of their z=0 counterparts of the same . For
IR galaxies, the mean ratios of the z=0.6 LIRGs (\rm
L_{dust} \sim 10^{11} L_\sun) are about a factor of 2 lower than local LIRGs,
whereas z=0.6 ULIRGs (\rm L_{dust} \sim 10^{12} L_\sun) have the same mean
ratios as their local counterparts. This is consistent
with the hypothesis that the dominant component of LIRG population has changed
from large, gas rich spirals at z to major-mergers at z=0. The stellar
mass of z=0.6 UV galaxies of \rm L_{FUV} \leq 10^{10.2} L_\sun is about a
factor 2 less than their local counterparts of the same luminosity, indicating
growth of these galaxies. The mass of z=0.6 UV lunmous galaxies (UVLGs: \rm
L_{FUV} > 10^{10.2} L_\sun) and IR selected galaxies, which are nearly
exclusively LIRGs and ULIRGs, is the same as their local counterparts.Comment: 27 pages, 8 figures, to be published in the Astrophysical Journal
Supplement series dedicated to GALEX result
Project overview and update on WEAVE: the next generation wide-field spectroscopy facility for the William Herschel Telescope
We present an overview of and status report on the WEAVE next-generation
spectroscopy facility for the William Herschel Telescope (WHT). WEAVE
principally targets optical ground-based follow up of upcoming ground-based
(LOFAR) and space-based (Gaia) surveys. WEAVE is a multi-object and multi-IFU
facility utilizing a new 2-degree prime focus field of view at the WHT, with a
buffered pick-and-place positioner system hosting 1000 multi-object (MOS)
fibres, 20 integral field units, or a single large IFU for each observation.
The fibres are fed to a single spectrograph, with a pair of 8k(spectral) x 6k
(spatial) pixel cameras, located within the WHT GHRIL enclosure on the
telescope Nasmyth platform, supporting observations at R~5000 over the full
370-1000nm wavelength range in a single exposure, or a high resolution mode
with limited coverage in each arm at R~20000. The project is now in the final
design and early procurement phase, with commissioning at the telescope
expected in 2017.Comment: 11 pages, 11 Figures, Summary of a presentation to Astronomical
Telescopes and Instrumentation 201
Galaxy Counts at 24 Microns in the SWIRE Fields
This paper presents galaxy source counts at 24 microns in the six Spitzer
Wide-field InfraRed Extragalactic (SWIRE) fields. The source counts are
compared to counts in other fields, and to model predictions that have been
updated since the launch of Spitzer. This analysis confirms a very steep rise
in the Euclidean-normalized differential number counts between 2 mJy and 0.3
mJy. Variations in the counts between fields show the effects of sample
variance in the flux range 0.5-10 mJy, up to 100% larger than Poisson errors.
Nonetheless, a "shoulder" in the normalized counts persists at around 3 mJy.
The peak of the normalized counts at 0.3 mJy is higher and narrower than most
models predict. In the ELAIS N1 field, the 24 micron data are combined with
Spitzer-IRAC data and five-band optical imaging, and these bandmerged data are
fit with photometric redshift templates. Above 1 mJy the counts are dominated
by galaxies at z less than 0.3. By 300 microJy, about 25% are between z ~
0.3-0.8, and a significant fraction are at z ~ 1.3-2. At low redshifts the
counts are dominated by spirals, and starbursts rise in number density to
outnumber the spirals' contribution to the counts below 1 mJy.Comment: 10 pages, 8 figures, accepted 3 November 2007 for publication in The
Astronomical Journal, formatted with emulateapj styl
Construction progress of WEAVE: the next generation wide-field spectroscopy facility for the William Herschel Telescope
We present an update on the overall construction progress of the WEAVE next-generation spectroscopy facility for the William Herschel Telescope (WHT), now that all the major fabrication contracts are in place. We also present a summary of the current planning behind the 5-year initial phase of survey operations, and some detailed end-to-end science simulations that have been effected to evaluate the final on-sky performance after data processing. WEAVE will provide optical ground-based follow up of ground-based (LOFAR) and space-based (Gaia) surveys. WEAVE is a multi-object and multi-IFU facility utilizing a new 2-degree prime focus field of view at the WHT, with a buffered pick-and-place positioner system hosting 1000 multi-object (MOS) fibres, 20 integral field units, or a single large IFU for each observation. The fibres are fed to a single (dual-beam) spectrograph, with total of 16k spectral pixels, located within the WHT GHRIL enclosure on the telescope Nasmyth platform, supporting observations at R 5000 over the full 370-1000nm wavelength range in a single exposure, or a high resolution mode with limited coverage in each arm at R 20000. The project has experienced some delays in procurement and now has first light expected for the middle of 2019
Construction progress of WEAVE: the next generation wide-field spectroscopy facility for the William Herschel Telescope
International audienceWe present an update on the overall construction progress of the WEAVE next-generation spectroscopy facility for the William Herschel Telescope (WHT), now that all the major fabrication contracts are in place. We also present a summary of the current planning behind the 5-year initial phase of survey operations, and some detailed end-to-end science simulations that have been effected to evaluate the final on-sky performance after data processing. WEAVE will provide optical ground-based follow up of ground-based (LOFAR) and space-based (Gaia) surveys. WEAVE is a multi-object and multi-IFU facility utilizing a new 2-degree prime focus field of view at the WHT, with a buffered pick-and-place positioner system hosting 1000 multi-object (MOS) fibres, 20 integral field units, or a single large IFU for each observation. The fibres are fed to a single (dual-beam) spectrograph, with total of 16k spectral pixels, located within the WHT GHRIL enclosure on the telescope Nasmyth platform, supporting observations at R 5000 over the full 370-1000nm wavelength range in a single exposure, or a high resolution mode with limited coverage in each arm at R 20000. The project has experienced some delays in procurement and now has first light expected for the middle of 2019