scholarly journals The Environments of Markarian Galaxies

1990 ◽  
Vol 124 ◽  
pp. 165-167
Author(s):  
John W. MacKenty ◽  
Brian McLean ◽  
Caroline Simpson
Keyword(s):  
Hubble Space Telescope ◽  
Ultraviolet Excess ◽  
Nuclear Activity ◽  
Space Telescope ◽  
Star Catalog ◽  
Guide Star ◽  
The Relationship ◽  
Peculiar Galaxies

The extensively studied Markarian sample of 1500 ultraviolet excess galaxies contains many Seyfert, starburst, and peculiar galaxies. Using the 20 minute V plates obtained for the construction of the Hubble Space Telescope Guide Star Catalog, we have investigated the morphologies of the Markarian galaxies and the environments in which they are located. This paper reports on the relationship between the types of nuclear activity and the morphologies and environments of the Markarian galaxies.

scholarly journals Photometric Calibrators for All-Sky Surveys: The GSPC-II Program

1994 ◽  
Vol 161 ◽  
pp. 301-303
Author(s):  
A. Ferrari ◽  
E.D. Siciliano ◽  
A. Pizzuti ◽  
B. Bucciarelli ◽  
G. Massone ◽  
...  
Keyword(s):  
Hubble Space Telescope ◽  
Stellar Populations ◽  
Galactic Structure ◽  
Mission Planning ◽  
Space Telescope ◽  
Sky Surveys ◽  
Star Catalog ◽  
Wide Range ◽  
The Uk ◽  
Guide Star

Accurate astrometric and photometric calibrations of all-sky photographic surveys, such as the Palomar Quick-V survey and the UK SERC-J survey, digitised for the construction of the Hubble Space Telescope Guide Star Catalog, are of extreme astrophysical value. Their wide range of applications includes, for example, galactic structure, stellar populations, extragalactic studies, and deep sky catalogs for mission planning and telescope operations. The Guide Star Photometric Catalog (GSPC-I, Lasker et al. 1988) provides stellar calibration sequences, placed approximately in the center of each survey plate, with a limiting magnitude of V = 15 mag. The goal of our program is to extend these calibrators to V = 20 mag in the Johnson-Kron-Cousins B, V and R passbands, with an accuracy of 0.05 mag. This is accomplished by taking CCD frames centered on the faintest star of each GSPC-I sequence. Typically, both long and short exposures are acquired in each field in order to link the bright and faint ends of the sequence.

scholarly journals The Guide Star Selection System and the Guide Star Catalog for Space Telescope

1986 ◽  
Vol 109 ◽  
pp. 721-727
Author(s):  
Jane L. Russell
Keyword(s):  
Production System ◽  
Selection System ◽  
Space Telescope ◽  
Star Catalog ◽  
Science Institute ◽  
Visual Magnitude ◽  
Photoelectric Measurements ◽  
Guide Star ◽  
Space Telescope Science Institute

The Guide Star Selection System (GSSS) will provide relative positions of two guide stars and the target for each observation of the Space Telescope as well as photometry for the guide stars. Being developed at the Space Telescope Science Institute, the GSSS is a production system which is based on PDS measurements of Schmidt survey plates. The specified accuracy for the system is +/−0.33 arcsec for the separation of the guide stars and 0.4 mag in the bandpass of the Space Telescope's Fine Guidance Sensors. The GSSS will produce two catalogs which will be used in the operation of the system. The Guide Star Photometry catalog includes photoelectric measurements (+/−0.05 mag) in B and V for six stars over the guide star range, 9.0 to 14.5 visual magnitude, near the central part of each 6 by 6 deg survey plate. The Guide Star Catalog will include the list of all possible guide stars and brighter, positions (at least +/−1 arcsec) and magnitudes (at least +/−0.4 mag) for essentially the whole sky complete to visual magnitude 15.

scholarly journals Hipparcos – The Tycho Input Catalogue

1986 ◽  
Vol 7 ◽  
pp. 713-717 ◽  
Author(s):  
J.L. Russell ◽  
D. Egret
Keyword(s):  
Additional Data ◽  
Hubble Space Telescope ◽  
A Priori ◽  
General Assembly ◽  
Space Telescope ◽  
Data Centre ◽  
Star Catalogue ◽  
Guide Star ◽  
Input Catalogue ◽  
Space Telescope Science Institute

AbstractThe Tycho Input Catalogue will be used as a finding list to identify the stellar data within the stream of raw data received from the Hipparcos star mappers. It is based on an a priori list of stars, namely the Guide Star Catalogue being created for the Hubble Space Telescope at the Space Telescope Science Institute. The Guide Star Catalogue will contain positions and magnitudes for objects in the sky complete to at least 14 mag, and will contain about 20 million stars. The data for the sky complete to approximately 12.5 mag, extracted from the Guide Star Catalogue, along with some additional data from the SIMBAD data base of about 500 000 stars at the Strasbourg Stellar Data Centre, will form the Tycho Input Catalogue of approximately 2 million objects. As of the 1985 IAU General Assembly nearly 50 per cent of the plates for the Guide Star Catalogue had been measured, and 10 per cent of them were completely processed and catalogued.

scholarly journals All NIRspec Needs is HST/WFC3 Pre-Imaging? The Use of Milky Way Stars in WFC3 Imaging to Register NIRspec MSA Observations

2016 ◽  
Vol 05 (03) ◽  
pp. 1650008
Author(s):  
B. W. Holwerda ◽  
R. J. Bouwens ◽  
M. Trenti ◽  
M. A. Kenworthy
Keyword(s):  
Near Infrared ◽  
Hubble Space Telescope ◽  
High Redshift ◽  
Wide Field ◽  
Galactic Latitude ◽  
Space Telescope ◽  
James Webb Space Telescope ◽  
Specific Formula ◽  
The Right ◽  
Guide Star

The James Webb Space Telescope (JWST) will be an exquisite new near-infrared observatory with imaging and multi-object spectroscopy through ESA’s NIRspec instrument with its unique Micro-Shutter Array (MSA), allowing for slits to be positioned on astronomical targets by opening specific [Formula: see text]-wide micro shutter doors. To ensure proper Target Acquisition (TA), the on-sky position of the MSA needs to be verified before spectroscopic observations start. An onboard centroiding program registers the position of pre-identified guide stars in a TA image, a short pre-spectroscopy exposure without dispersion (image mode) through the MSA with all shutters open. The outstanding issue is the availability of Galactic stars in the right luminosity range for TA relative to typical high redshift targets. We explore this here using the stars and [Formula: see text] candidate galaxies identified in the source extractor catalogs of Brightest of Reionizing Galaxies survey (BoRG[z8]), a pure-parallel program with Hubble Space Telescope Wide-Field Camera 3. We find that (a) a single WFC3 field contains enough Galactic stars to satisfy the NIRspec astrometry requirement (20 milli-arcseconds), provided its and the NIRspec TA’s are [Formula: see text] AB in WFC3 [Formula: see text], (b) a single WFC3 image can therefore serve as the pre-image if need be, (c) a WFC3 mosaic and accompanying TA image satisfy the astrometry requirement at [Formula: see text] AB mag in WFC3 [Formula: see text], (d) no specific Galactic latitude requires deeper TA imaging due to a lack of Galactic stars, and (e) a depth of [Formula: see text] AB mag in WFC3 [Formula: see text] is needed if a guide star in the same MSA quadrant as a target is required. We take the example of a BoRG identified [Formula: see text] candidate galaxy and require a Galactic star within 20[Formula: see text] of it. In this case, a depth of 25.5 AB in [Formula: see text] is required (with [Formula: see text]97% confidence).

scholarly journals A nearby luminous AGN sample optically selected from Hubble Space Telescope

2019 ◽  
Vol 490 (3) ◽  
pp. 3793-3798 ◽  
Author(s):  
Shuang-Liang Li
Keyword(s):  
Active Galactic Nucleus ◽  
Very Long Baseline Interferometry ◽  
Hubble Space Telescope ◽  
Radio Flux ◽  
Space Telescope ◽  
Very Large Array ◽  
X Ray ◽  
Long Baseline ◽  
Very Long Baseline Array ◽  
The Relationship

ABSTRACT In this work, a nearby luminous active galactic nucleus (AGN) sample is selected from Hubble Space Telescope(HST), where only sources with both X-ray emission observed by Chandra/XMM–Newton and radio flux detected by Very Large Array (VLA)/Very Long Baseline Array (VLBA)/very long baseline interferometry (VLBI)/Multi-Element Radio Linked Interferometer Network (MERLIN) are adopted to keep high precision. Finally, we get a sample of 30 luminous AGNs, which consists of 11 radio-loud AGNs (RLAGN) and 19 radio-quiet AGNs (RQAGN). It is found that the relationship between RUV and αox, which was first reported by Li & Xie in low-luminosity AGNs (LLAGN), and other relationships are all absent in RLAGN, probably due to the complex physical process therein. Our results indicate that the X-ray emission from jet should play an important role in RLAGN and further support the transition of accretion mode between LLAGN and RLAGN. On the other hand, the traditional relationships in RQAGN, such as αox and λ, Γ and λ, are found to be well consistent with previous works.

scholarly journals The GSC-II catalog release GSC 2.3: description and properties

2007 ◽  
Vol 3 (S248) ◽  
pp. 316-319 ◽  
Author(s):  
B. Bucciarelli ◽  
M. G. Lattanzi ◽  
B. McLean ◽  
R. Drimmel ◽  
G. Greene ◽  
...  
Keyword(s):  
Space Telescope ◽  
Star Catalog ◽  
Science Institute ◽  
Guide Star ◽  
Star Classification ◽  
Space Telescope Science Institute ◽  
A Current ◽  
Multi Band

AbstractThe GSC 2.3 is a current catalog release extracted from the Guide Star Catalog II database, which is maintained at the Space Telescope Science Institute in Baltimore, USA. The catalog contains astrometry, multi-band photometry (BJ,RJ,IN) and star/non-star classification for 945,592,683 objects down to the magnitude limit of the survey plates. We review the performance of stellar parameters, anticipating the improvements in astrometric accuracy foreseen by its recalibration with the newly available catalog in the UCAC series.

Optimisation of JWST operations with the help of Gaia

2017 ◽  
Vol 12 (S330) ◽  
pp. 98-99
Author(s):  
J. Sahlmann ◽  
E. G. Nelan ◽  
P. Chayer ◽  
B. McLean ◽  
M. Lallo
Keyword(s):  
Focal Plane ◽  
Space Telescope ◽  
Star Catalog ◽  
Science Institute ◽  
James Webb Space Telescope ◽  
Survey Results ◽  
Guide Star ◽  
Operations Center ◽  
Space Telescope Science Institute ◽  
Operational Aspects

AbstractThe James Webb Space Telescope (JWST) is scheduled for launch in 2018. To operate and observe efficiently, JWST will rely on various external astrometric and photometric catalogues, in particular the HST Guide Star Catalog (GSC), for instance to locate sources accurately on the sky. The incorporation of the Gaia astrometric catalog will improve the absolute astrometry of the GSC and is therefore relevant for JWST operations. We outline how the JWST Science and Operations Center hosted at the Space Telescope Science Institute (STScI) intends to use the Gaia survey results to improve upon operational aspects such as the guiding and the geometric focal plane characterisation of JWST.

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