4,401 research outputs found
Optical Images and Source Catalog of AKARI North Ecliptic Pole Wide Survey Field
We present the source catalog and the properties of the , and
band images obtained to support the {\it AKARI} North Ecliptic Pole Wide
(NEP-Wide) survey. The NEP-Wide is an {\it AKARI} infrared imaging survey of
the north ecliptic pole covering a 5.8 deg area over 2.5 -- 6 \micron
wavelengths. The optical imaging data were obtained at the Maidanak Observatory
in Uzbekistan using the Seoul National University 4k 4k Camera on the
1.5m telescope. These images cover 4.9 deg where no deep optical imaging
data are available. Our , and band data reach the depths of
23.4, 23.1, and 22.3 mag (AB) at 5, respectively. The
source catalog contains 96,460 objects in the band, and the astrometric
accuracy is about 0.15\arcsec at 1 in each RA and Dec direction.
These photometric data will be useful for many studies including identification
of optical counterparts of the infrared sources detected by {\it AKARI},
analysis of their spectral energy distributions from optical through infrared,
and the selection of interesting objects to understand the obscured galaxy
evolution.Comment: 39 pages, 12 figure
Web-Based Visualization of Very Large Scientific Astronomy Imagery
Visualizing and navigating through large astronomy images from a remote
location with current astronomy display tools can be a frustrating experience
in terms of speed and ergonomics, especially on mobile devices. In this paper,
we present a high performance, versatile and robust client-server system for
remote visualization and analysis of extremely large scientific images.
Applications of this work include survey image quality control, interactive
data query and exploration, citizen science, as well as public outreach. The
proposed software is entirely open source and is designed to be generic and
applicable to a variety of datasets. It provides access to floating point data
at terabyte scales, with the ability to precisely adjust image settings in
real-time. The proposed clients are light-weight, platform-independent web
applications built on standard HTML5 web technologies and compatible with both
touch and mouse-based devices. We put the system to the test and assess the
performance of the system and show that a single server can comfortably handle
more than a hundred simultaneous users accessing full precision 32 bit
astronomy data.Comment: Published in Astronomy & Computing. IIPImage server available from
http://iipimage.sourceforge.net . Visiomatic code and demos available from
http://www.visiomatic.org
Adaptive Optics observations of LBQS 0108+0028: K-band detection of the host galaxy of a radio-quiet QSO at z=2
We report the first unambiguous detection of the host galaxy of a normal
radio-quiet QSO at high-redshift in K-band. The luminosity of the host
comprises about 35% of the total K-band luminosity. Assuming the average colour
of QSOs at z=2, the host would be about 5 to 6 mag brighter than an unevolved
L* galaxy placed at z=2, and 3 to 4 mag brighter than a passively evolved L*
galaxy at the same redshift. The luminosity of the host galaxy of the QSO would
thus overlap with the highest found in radio-loud QSOs and radio-galaxies at
the same redshift.Comment: Accepted to be published in MNRAS. 4 pages, 2 postscript figures.
Also available at http://www.mpa-garching.mpg.de/~itzia
AKARI Mission Program: Excavating Mass Loss History in Extended Dust Shells of Evolved Stars (MLHES) I. Far-IR Photometry
We performed a far-IR imaging survey of the circumstellar dust shells of 144
evolved stars as a mission programme of the AKARI infrared astronomical
satellite using the Far-Infrared Surveyor (FIS) instrument. With this survey,
we deliver far-IR surface brightness distributions of roughly 10' x 40' or 10'
x 20' areas of the sky around the target evolved stars in the four FIS bands at
65, 90, 140, and 160 microns. Our objectives are to characterize the far-IR
surface brightness distributions of the cold dust component in the
circumstellar dust shells, from which we derive the amount of cold dust grains
as low as 20 K and empirically establish the history of the early mass loss
history. In this first installment of the series, we introduce the project and
its aims, describe the observations, data reduction, and surface brightness
correction process, and present the entire data set along with the results of
integrated photometry measurements (i.e., the central source and circumstellar
dust shell altogether). We find that (1) far-IR emission is detected from all
but one object at the spatial resolution about 30" - 50" in the corresponding
bands, (2) roughly 60 - 70 % of the target sources show some extension, (3)
previously unresolved nearby objects in the far-IR are now resolved around 28
target sources, (4) the results of photometry measurements are reasonable with
respect to the entries in the AKARI/FIS Bright Source Catalogue, despite the
fact that the targets are assumed to be point-sources when catalogue flux
densities were computed, and (5) an IR two-color diagram would place the target
sources in a roughly linear distribution that may correlate with the age of the
circumstellar dust shell and can potentially be used to identify which targets
are more extended than others.Comment: To be published in PASJ AKARI Special Issue: 25 pages, 5 figures, 5
tables (and 28 supplementary figures available only in PASJ on-line
Obscured clusters.IV. The most massive stars in [DBS2003]179
Aims. We report new results for the massive evolved and main sequence members
of the young galactic cluster DBS2003 179. We determine the physical parameters
and investigate the high-mass stellar content of the cluster, as well as of its
close vicinity. Methods. Our analysis is based on ISAAC/VLT moderate-resolution
(R\approx4000) infrared spectroscopy of the brightest cluster members. We
derive stellar parameters for sixteen of the stellar members, using full
non-LTE modeling of the obtained spectra. Results. The cluster contains three
late WN or WR/LBV stars (Obj 4, Obj 15, and Obj 20:MDM32) and at least 5 OIf
and 5 OV stars. According to the Hertzsprung-Russell diagram for DBS2003 179,
the WR stars show masses above 85Msun, the OIf stars are between 40 and 80Msun,
and the main sequence O stars are >20Msun. There are indications of binarity
for Obj 4 and Obj 11, and Obj 3 shows a variable spectrum. The cluster is
surrounded by a continuous protostar formation region most probably triggered
by DBS2003 179. Conclusions. We confirm that DBS2003 179 is young massive
cluster (2.5 10^4Msun) very close to the Galactic center at the distance of
7.9+-0.8 kpc.Comment: 14 pages, 16 figures, accepted in A&
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