Status Report

NASA Hubble Space Telescope Daily Status Report #4078

By SpaceRef Editor
March 27, 2006
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NASA Hubble Space Telescope Daily Status Report #4078

HUBBLE SPACE TELESCOPE – Continuing to collect World Class Science


PERIOD COVERED: UT March 24,25,26, 2006 (DOY 083,084,085)


NIC1/NIC2/NIC3 8793

NICMOS Post-SAA calibration – CR Persistence Part 4

A new procedure proposed to alleviate the CR-persistence problem of NICMOS. Dark frames will be obtained immediately upon exiting the SAA contour 23, and every time a NICMOS exposure is scheduled within 50 minutes of coming out of the SAA. The darks will be obtained in parallel in all three NICMOS Cameras. The POST-SAA darks will be non-standard reference files available to users with a USEAFTER date/time mark. The keyword ‘USEAFTER=date/time’ will also be added to the header of each POST-SAA DARK frame. The keyword must be populated with the time, in addition to the date, because HST crosses the SAA ~8 times per day so each POST-SAA DARK will need to have the appropriate time specified, for users to identify the ones they need. Both the raw and processed images will be archived as POST-SAA DARKSs. Generally we expect that all NICMOS science/calibration observations started within 50 minutes of leaving an SAA will need such maps to remove the CR persistence from the science images. Each observation will need its own CRMAP, as different SAA passages leave different imprints on the NICMOS detectors.

ACS/WFC 10762

The Long X-ray Jet of Quasar 4C19.44

We propose to obtain a high signal/noise image of the very long jet of 4C 19.44. The observation should provide sufficient counts per jet feature to obtain X-ray spectral indices capable of discriminating between spectral models of the jet. We will examine the data for offsets between X-ray and radio features and compare the beaming of the kpc jet with the information obtained from the pc scale using VLBI.


CCD Hot Pixel Annealing

Hot pixel annealing will continue to be performed once every 4 weeks. The CCD TECs will be turned off and heaters will be activated to bring the detector temperatures to about +20C. This state will be held for approximately 6 hours, after which the heaters are turned off, the TECs turned on, and the CCDs returned to normal operating condition. To assess the effectiveness of the annealing, a bias and four dark images will be taken before and after the annealing procedure for both WFC and HRC. The HRC darks are taken in parallel with the WFC darks. The charge transfer efficiency {CTE} of the ACS CCD detectors declines as damage due to on-orbit radiation exposure accumulates. This degradation has been closely monitored at regular intervals, because it is likely to determine the useful lifetime of the CCDs. We combine the annealling activity with the charge transfer efficiency monitoring and also merge into the routine dark image collection. To this end, the CTE monitoring exposures have been moved into this proposal . All the data for this program is acquired using internal targets {lamps} only, so all of the exposures should be taken during Earth occultation time {but not during SAA passages}. This program emulates the ACS pre-flight ground calibration and post-launch SMOV testing {program 8948}, so that results from each epoch can be directly compared. Extended Pixel Edge Response {EPER} and First Pixel Response {FPR} data will be obtained over a range of signal levels for both the Wide Field Channel {WFC}, and the High Resolution Channel {HRC}.


ACS CCDs daily monitor

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 programme will be for the entire lifetime of ACS. Changes from cycle 13:- The default gain for WFC is 2 e-/DN. As before bias frames will be collected for both gain 1 and gain 2. Dark frames are acquired using the default gain {2}. This program cover the period Oct, 2 2005- May, 29-2006. The second half of the program has a different proposal number: 10758.

FGS 10612

Binary Stars in Cyg OB2: Relics of Massive Star Formation in a Super-Star Cluster

We propose to make a high angular resolution SNAP survey of the massive stars in the nearby, super-star cluster Cyg OB2. We will use FGS1r TRANS mode observations to search for astrometric companions in the separation range of 0.01 to 1.00 arcsec and in the magnitude difference range smaller than 4 magnitudes. The observations will test the idea that the formation of very massive stars involves mergers and the presence of nearby companions. Discovery of companions to massive stars in this relatively nearby complex will provide guidance in the interpretation of apparently supermassive stars in distant locations. The search for companions will also be important for verification of fundamental parameters derived from spectroscopy, adjustments to main sequence fitting and distance estimations, determining third light contributions of eclipsing binaries, identifying wide colliding wind binaries, studying the relationship between orbital and spin angular momentum, and discovering binaries amenable to future mass determinations. The massive star environment in Cyg OB2 may be similar to the kinds found in the earliest epoch of star formation, so that a study of the role of binaries in Cyg OB2 will help us understand the formation processes of the first stars in the Universe.

FGS 10610

Astrometric Masses of Extrasolar Planets and Brown Dwarfs

We propose observations with HST/FGS to estimate the astrometric elements {perturbation orbit semi-major axis and inclination} of extra-solar planets orbiting six stars. These companions were originally detected by radial velocity techniques. We have demonstrated that FGS astrometry of even a short segment of reflex motion, when combined with extensive radial velocity information, can yield useful inclination information {McArthur et al. 2004}, allowing us to determine companion masses. Extrasolar planet masses assist in two ongoing research frontiers. First, they provide useful boundary conditions for models of planetary formation and evolution of planetary systems. Second, knowing that a star in fact has a plantary mass companion, increases the value of that system to future extrasolar planet observation missions such as SIM PlanetQuest, TPF, and GAIA.

ACS/WFC 10605

Quantifying Star Formation and Feedback: The M81 Group Dwarf Galaxies

Studies of the impact of star formation via stellar winds and supernovae {‘feedback’} on the properties of a galaxy are of fundamental importance to understanding galaxy evolution. One crucial aspect in these studies is a precise census of the recent star formation in a galaxy. The aim of this proposal is to obtain spatially resolved star formation histories with a time resolution of roughly 30 Myr over the last 500 Myr in a carefully designed sample using the absolutely unique capabilities of the ACS. Our sample comprises 10 galaxies in the M81 group which is host to a wide diversity of dwarf star forming galaxies. They span ranges of 6 magnitudes in luminosity, 1000 in current star formation rate, and 0.5 dex in metallicity. The ACS observations will allow us to directly observe the strength and spatial relationships of all of the star formation in these galaxies in the last 500 Myr. We can then quantify the star formation and measure {1} the fraction of star formation that is triggered by feedback, {2} the fraction of star formation that occurs in clusters and associations, and {3} to what degree future star formation is governed by the feedback from previous star formation. The ACS observations will be complemented with high-quality ancillary data collected by our team for all galaxies {e.g., Spitzer, UV/optical/NIR, VLA HI}. We will calculate the energy created by star formation events and compare it to the estimated energy deposited into the local ISM. This will enable us to construct prescriptions of how star formation and feedback depend on metallicity, size, gas content, and current star formation rates in galaxies. Our resolved star formation maps will be compared with star formation rates inferred from H-alpha, UV, and IR observations – allowing an independent calibration of these techniques. Recent ACS imaging by us of one galaxy in the same group clearly demonstrates the feasibility of the proposed program. Most of the sample galaxies are located in the CVZ, making this an extremely efficient program.

NIC2 10603

Multiwavelength Imaging of Edge-on Protoplanetary Disks: Quantifying the Growth of Circumstellar Dust

Young, edge-on circumstellar disks are uniquely valuable laboratories for the study of planet formation. In these objects, the central star is occulted from direct view, significant PSF artifacts are absent, and the disk is clearly seen as a central dust lane flanked by faint disk reflected light. The detailed morphology of these nebulae and its variation with wavelength provide crucial information on the disk internal structure and the properties of its constituent dust grains. A key observable is the slope defining the wavelength dependence of the dust scattering opacity, which becomes shallower when grain growth has taken place; multiwavelength resolved disk images are the key dataset enabling such measurements. Recent analyses of three different edge-on disks have revealed a diversity in their dust properties that is indicative of different degrees of dust grain evolution having taken place in each system. This characterization of disk grain growth, when applied comparatively to a larger sample of these objects, would enable the construction of an evolutionary sequence of young disks at successive stages on the road to planet formation. In pursuit of this goal, we have identified a sample of 15 edge-on disks previously discovered by HST or groundbased telescopes, but for which high fidelity, high spatial resolution images do not yet exist in both the optical and near-infrared. We propose broad-band multicolor imaging with NICMOS of all these targets, and ACS imaging of nine of these targets In combination with existing data, the proposed images will form a complete database of high resolution optical/near-IR images for these 15 disk systems. Scattered light modeling will be used to derive the disk structure and dust properties, yielding results that will be of fundamental importance for our understanding of grain properties during protoplanetary disk evolution.

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.


The link between X-ray source and stellar populations in M81

We propose to perform a deep v~26-27.0 HST-ACS survey of the nearby {3.6 Mpc} spiral galaxy M~81 in order to study the nature of its X-ray source populations detected with Chandra. For the first time in a galaxy other than the Milky-Way or the Magelanic Clouds, we will classify X-ray sources as High-Mass and Low-Mass X-ray binaries {HMXBs, LMXBs} and investigate how these populations depend on their galactic environment. The classification will be performed {a} by finding and classifying unique optical counterparts for the X-ray sources and {b} studying the stellar populations in their vicinity. Both tasks require the <0.1'' resolution of HST-ACS which matches well the positional accuracy of Chandra. Finally we will use these results together with X-ray binary evolution synthesis models in order to constrain X-ray binary {XRB} evolution channels. These data will also be a great resource for studies of the star-formation and star- cluster populations in one of the prototypical spiral galaxies.

ACS/WFC 10582

Probing The Galaxy-wide Globular Cluster – Low Mass X-ray Binary Connection in Early-type Galaxies

The combination of high-resolution imaging from Hubble {HST} and Chandra {CXO} has completely revolutionized our understanding of extragalactic low-mass X-ray binaries {LMXBs} and globular clusters {GCs}; however, studies have been limited by short X-ray exposures and relatively small fields. NGC 4697 amd NGC 4365 are relatively simple elliptical galaxies in the X- ray that will have deep CXO observations. We propose ACS observations in six flanking fields per galaxy to provide a study of the GC-LMXB connection in normal early-type galaxies with unprecedented depth, spatial resolution and areal coverage. Combined with existing central field observations, we will detect ~900 and ~2700 GCs GCs in most of NGC 4697 and all of NGC 4365. These two galaxies will have the greatest number of detected GC-LMXBs to date {~70 & 120}. We will measure the fraction of LMXBs found in GCs, and the fraction of GCs which contain LMXBs, as a function of X-ray luminosity, galactocentric distance, color, GC half-light radius, and local GC specific frequency. We will test existing models of GC formation/evolution and LMXB formation/evolution. Using the radial profile of optical light, GCs, and LMXBS, we will determine the percentage of field LMXBs which may have originated in GCs.

ACS/WFC 10496

Decelerating and Dustfree: Efficient Dark Energy Studies with Supernovae and Clusters

We propose a novel HST approach to obtain a dramatically more useful “dust free” Type Ia supernovae {SNe Ia} dataset than available with the previous GOODS searches. Moreover, this approach provides a strikingly more efficient search-and-follow-up that is primarily pre- scheduled. The resulting dark energy measurements do not share the major systematic uncertainty at these redshifts, that of the extinction correction with a prior. By targeting massive galaxy clusters at z > 1 we obtain a five-times higher efficiency in detection of Type Ia supernovae in ellipticals, providing a well-understood host galaxy environment. These same deep cluster images then also yield fundamental calibrations required for future weak lensing and Sunyaev-Zel’dovich measurements of dark energy, as well as an entire program of cluster studies. The data will make possible a factor of two improvement on supernova constraints on dark energy time variation, and much larger improvement in systematic uncertainty. They will provide both a cluster dataset and a SN Ia dataset that will be a longstanding scientific resource.

ACS/WFC 10493

A Survey for Supernovae in Massive High-Redshift Clusters

We propose to measure, to an unprecedented 30% accuracy, the SN-Ia rate in a sample of massive z=0.5-0.9 galaxy clusters. The SN-Ia rate is a poorly known observable, especially at high z, and in cluster environments. The SN rate and its redshift dependence can serve as powerful discrimiminants for a number of key issues in astrophysics and cosmology. Our observations will: 1. Put clear constraints on the characteristic SN-Ia “delay time, ” the typical time between the formation of a stellar population and the explosion of some of its members as SNe-Ia. Such constraints can exclude entire categories of SN-Ia progenitor models, since different models predict different delays. 2. Help resolve the question of the dominant source of the high metallicity in the intracluster medium {ICM} – SNe-Ia, or core-collapse SNe from an early stellar population with a top-heavy IMF, perhaps those population III stars responsible for the early re-ionization of the Universe. Since clusters are excellent laboratories for studying enrichment {they generally have a simple star-formation history, and matter cannot leave their deep potentials}, the results will be relevant for understanding metal enrichment in general, and the possible role of first generation stars in early Universal enrichment. 3. Reveal, via nuclear variability, the AGN fraction in clusters at this redshift, to be compared with the field AGN fraction. This will be valuable input for understanding black-hole demographics, AGN evolution, and ICM energetics. 4. Potentially discover intergalactic cluster SNe, which can trace the stripped stellar population at high z.

ACS/WFC 10475

An ACS H-alpha Survey of the Carina Nebula

We propose an H-alpha ACS imaging survey covering 540 square arcminutes of the Carina Nebula, including an unbiased survey of the bright core, and several prominent dust pillars in the rich southern region of the nebula. Carina provides an important link between well-studied nearby H II regions like Orion, and more distant mini-starbusts like 30 Doradus. CVZ orbits will allow extremely efficient use of HST to map a large area of this complex and important region — more than 95 percent of the proposed survey will be observed by HST for the first time. This survey will provide a complete census of microjets, proplyds, and silhouette disks with diameters as small as 200 AU, enough to spatially resolve disks like those in Orion, and will provide the first catalog of outflows {jets} from embedded low-mass stars, thin filamentary shocks, and wind-wind collisions in Carina. An accurate census of these phenomena is needed to characterize the star formation activity and gas dynamics as a function of position in the nebula, and to determine if models for protoplanetary disk evaporation from Orion are applicable in more extreme regions. Our previous ground-based optical and IR surveys have already revealed dozens of candidates for this type of activity — but this is just the tip of the iceberg. Our proposed HST/ACS survey promises to be a bonanza for understanding ongoing low-mass star formation influenced by extremely high-mass stars.

ACS/WFC 10334

i-Band Dropouts around High-z Radio Quasars

We will carry out deep F606W/F814W or F775W/F850LP imaging of three high-redshift radio quasars to search for an excess of dropouts. Also see program 9291 and 9777.

NIC2 10173

Infrared Snapshots of 3CR Radio Galaxies

Radio galaxies are an important class of extragalactic objects: they are one of the most energetic astrophysical phenomena and they provide an exceptional probe of the evolving Universe, lying typically in high density regions but well-represented across a wide redshift range. In earlier Cycles we carried out extensive HST observations of the 3CR sources in order to acquire a complete and quantitative inventory of the structure, contents and evolution of these important objects. Amongst the results, we discovered new optical jets, dust lanes, face-on disks with optical jets, and revealed point-like nuclei whose properties support FR-I/BL Lac unified schemes. Here, we propose to obtain NICMOS infrared images of 3CR sources with z<0.3 as a major enhancement to an already superb dataset. We aim to deshroud dusty galaxies, study the underlying host galaxy free from the distorting effects of dust, locate hidden regions of star formation and establish the physical characteristics of the dust itself. We will measure frequency and spectral energy distributions of point-like nuclei, expected to be stronger and more prevalent in the IR, seek spectral turnovers in known synchrotron jets and find new jets. We will strongly test unified AGN schemes and merge these data with existing X-ray to radio observations. The resulting database will be an incredibly valuable resource to the astronomical community for years to come.


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

HSTARS: (None)



                         SCHEDULED      SUCCESSFUL
FGS GSacq               25                    25
FGS REacq               12                    12
OBAD with Maneuver   72                    72


ACS OPS Request 17673 was excuted after ACS transition from Anneal to Operate (normal SMS commanding) at 084/11:17 . This Ops Request set the STB error actions to Suspend for the following: – 915 Insufficient Parameters

– 917 Invalid Macro Number

– 925 Invalid Channel ID

– 926 Invalid Immediate Macro Number

– 927 Invalid Operate Immediate Macro

– 928 Invalid Operate Normal Macro

These changes to the ACS STB error actions were agreed to at the Operations Briefing/Status meeting which was held on March 24, 2006 at 3:00 pm to discuss the ACS Day 077 Bad Command FIFO Data Anomaly (HSTAR 10173) post-anomaly analysis.

SpaceRef staff editor.