Status Report

NASA Hubble Space Telescope Daily Report #3948

By SpaceRef Editor
September 20, 2005
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HUBBLE SPACE TELESCOPE – Continuing to collect World Class Science

DAILY REPORT        # 3948

PERIOD COVERED: UT September 19, 2005 (DOY 262)


ACS/HRC 10377

ACS Earth Flats

High signal sky flats will be obtained by observing the bright Earth with the HRC and WFC. These observations will be used to verify the accuracy of the flats currently used by the pipeline and will provide a comparison with flats derived via other techniques: L-flats from stellar observations, sky flats from stacked GO observations, and internal flats using the calibration lamps. Weekly coronagraphic monitoring is required to assess the changing position of the spots.


ACS CCDs daily monitor – Cycle 13 – Part 2

This program consists of a set of basic tests to monitor, the read noise, the development of hot pixels and test for any source of noise in ACS CCD detectors. The files, biases and dark will be used to create reference files for science calibration. This program will be for the entire lifetime of ACS.

ACS/WFC 10187

Direct imaging of the progenitors of massive, core-collapse supernovae

Modern supernovae searches in the nearby Universe are discovering large numbers of SNe which have massive star progenitors {Types II, Ib and Ic}. The extensive HST image archives of galaxies within ~20Mpc enables their individual bright stellar content to be resolved. As massive, evolved stars are the most luminous single objects in a galaxy, the progenitors of core-collapse SNe should be directly detectable on pre-explosion images. In our ongoing HST programme we have detected the first red supergiant progenitor of a normal type II supernova, shown that SN 1993J came from a binary system, and set direct mass-limits on three other type II supernovae progenitors. These discoveries are providing strong constraints on theoretical models of pre- supernova stellar evolution that predict which stars produce which type of supernovae. We request time to continue this successful project, and require ACS observations of future SNe which are discovered in galaxies closer than 20Mpc which have pre-explosion HST archive images available. These observations will allow the SNe to be precisely positioned on the pre- explosion frames with the required astrometric accuracy of around 0.05″, and provide 3-colour photometry of the surrounding stellar populations for reddening estimations. The goal of this project is to directly identify the progenitor stars of core-collapse supernovae. We will compare the results to our own stellar evolutionary tracks in order to determine masses or restrictive mass-limits for the progenitors.

ACS/WFC 10581

Imaging a Proto-cluster at z=2.3: The Morphology-Density Relation at High Redshift

We propose deep ACS/WFC imaging in the HS1700+643 field, which contains a significant galaxy over-density at z=2.30+/-0.015. This structure is the largest and most robustly established cluster-sized over-density at z>1.5. We have spectroscopically confirmed 100 z~2 star-forming galaxies in this field and find significant differences in their stellar populations as a function of large-scale environment. Here we propose to measure the detailed morphological properties of this sample, to determine if the universal morphology-density relationship observed in the low-redshift universe is already in place in and around a forming proto-cluster region at high redshift. As well as providing a unique window into galaxy formation through studies of the z=2.3 proto-cluster, the HS1700+643 field has an extensive wealth of complementary data to recommend it. We will combine the new ACS observations with existing multi-wavelength imaging ranging from 0.3–8.0 microns, optical and near-IR spectroscopy, and narrow band imaging of z=2.3 H-alpha emitters, to understand the evolving properties of a complete and unbiased sample of high-redshift galaxies.

ACS/WFC 10592

An ACS Survey of a Complete Sample of Luminous Infrared Galaxies in the Local Universe

At luminosities above 10^11.4 L_sun, the space density of far-infrared selected galaxies exceeds that of optically selected galaxies. These `luminous infrared galaxies’ {LIRGs} are primarily interacting or merging disk galaxies undergoing enhanced star formation and Active Galactic Nuclei {AGN} activity, possibly triggered as the objects transform into massive S0 and elliptical merger remnants. We propose ACS/WFC imaging of a complete sample of 88 L_IR > 10^11.4 L_sun luminous infrared galaxies in the IRAS Revised Bright Galaxy Sample {RBGS: i.e., 60 micron flux density > 5.24 Jy}. This sample is ideal not only in its completeness and sample size, but also in the proximity and brightness of the galaxies. The superb sensitivity, resolution, and field of view of ACS/WFC on HST enables a unique opportunity to study the detailed structure of galaxies that sample all stages of the merger process. Imaging will be done with the F439W and F814W filters {B and I-band} to examine as a function of both luminosity and merger state {i} the evidence at optical wavelengths of star formation and AGN activity and the manner in which instabilities {bars and bridges} in the galaxies may funnel material to these active regions, {ii} the relationship between star formation and AGN activity, and {iii} the structural properties {AGN, bulge, and disk components} and fundamental parameters {effective radius and surface brightness} of LIRGs and their similarity with putative evolutionary byproducts {elliptical, S0 and classical AGN host galaxies}. This HST survey will also bridge the wavelength gap between a Spitzer imaging survey {covering seven bands in the 3.6-160 micron range} and a GALEX UV imaging survey of these galaxies, but will resolve complexes of star clusters and multiple nuclei at resolutions well beyond the capabilities of either Spitzer or GALEX. The combined datasets will result in the most comprehensive multiwavelength study of interacting and merging galaxies to date.

ACS/WFC 10626

A Snapshot Survey of Brightest Cluster Galaxies and Strong Lensing to z = 0.9

We propose an ACS/WFC snapshot survey of the cores of 150 rich galaxy clusters at 0.3 < z < 0.9 from the Red Sequence Cluster Survey {RCS}. An examination of the galaxian light in the brightest cluster galaxies, coupled with a statistical analysis of the strong-lensing properties of the sample, will allow us to contrain the evolution of both the baryonic and dark mass in cluster cores, over an unprecedented redshift range and sample size. In detail, we will use the high- resolution ACS images to measure the metric {10 kpc/h} luminosity and morphological disturbances around the brightest clusters galaxies, in order to calibrate their accretion history in comparison to recent detailed simulations of structure formation in cluster cores. These images will also yield a well-defined sample of arcs formed by strong lensing by these clusters; the frequency and detailed distribution {size, multiplicity, redshifts} of these strong lens systems sets strong constraints on the total mass content {and its structure} in the centers of the clusters. These data will also be invaluable in the study of the morphological evolution and properties of cluster galaxies over a significant redshift range. These analyses will be supported by extensive ongoing optical and near-infrared imaging, and optical spectroscopy at Magellan, VLT and Gemini telescopes, as well as host of smaller facilities.

ACS/WFC 10711

Hubble Heritage Observations of NGC1309

The Hubble Heritage team will use a single pointing of ACS WFC to obtain F435W images of NGC 1309 as part of a public release image.

WFPC2 10356

WFPC2 Cycle 13 Decontaminations and Associated Observations

This proposal is for the monthly WFPC2 decons. Also included are instrument monitors tied to decons: photometric stability check, focus monitor, pre- and post-decon internals {bias, intflats, kspots, & darks}, UV throughput check, VISFLAT sweep, and internal UV flat check.

WFPC2 10359

WFPC2 CYCLE 13 Standard Darks

This dark calibration program obtains dark frames every week in order to provide data for the ongoing calibration of the CCD dark current rate, and to monitor and characterize the evolution of hot pixels. Over an extended period these data will also provide a monitor of radiation damage to the CCDs.


Significant Spacecraft Anomalies: (The following are preliminary reports of potential non-nominal performance that will be investigated.)

HSTARS: (None)



                             SCHEDULED     SUCCESSFUL 
 Gsacq                   09                      09 

FGS Reacq                   02                      02 
 OBAD with Maneuver     22                      22 


SpaceRef staff editor.