Status Report

NASA Hubble Space Telescope Daily Report #3972

By SpaceRef Editor
October 24, 2005
Filed under , ,

HUBBLE SPACE TELESCOPE – Continuing to collect World Class Science


PERIOD COVERED: UT October 21,22.23, 2005 (DOY 294,295,296)


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/SBC 10739

Internal Flat Field Stability

The stability of the CCD flat fields will be monitored using the calibration lamps and a sub-sample of the filter set. For the SBC imaging filters, differences in the low-frequency flat field structure with wavelength will be assessed. New high signal P-flats will be obtained for the SBC prisms.

ACS/HRC 10738

Earth Flats

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 in the pipeline and to monitor any changes. Weekly coronagraphic monitoring is required to assess the changing position of the spots.


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.

ACS/WFC/NIC3 10632

Searching for galaxies at z>6.5 in the Hubble Ultra Deep Field

We propose to obtain deep ACS {F606W, F775W, F850LP} imaging in the area of the original Hubble Ultra Deep Field NICMOS parallel fields and – through simultaneous parallel observations – deep NICMOS {F110W, F160W} imaging of the ACS UDF area. Matching the extreme imaging depth in the optical and near-IR bands will result in seven fields with sufficiently sensitive multiband data to detect the expected typical galaxies at z=7 and 8. Presently no such a field exist. Our combined optical and near-IR ultradeep fields will be in three areas separated by about 20 comoving Mpc at z=7. This will allow us to give a first assessment of the degree of cosmic variance. If reionization is a process extending over a large redshift interval and the luminosity function doesn’t evolve strongly beyond z=6, these data will allow us to identify of the order of a dozen galaxies at 6.56.5. Conversely, finding fewer objects would be an indication that the bulk of reionization is done by galaxies at z=6. By spending 204 orbits of prime HST time we will capitalize on the investment of 544 prime orbits already made on the Hubble Ultra Deep Field {UDF}. We have verified that the program as proposed is schedulable and that it will remain so even if forced to execute in the 2-gyro mode. The data will be non-proprietary and the reduced images will be made public within 2 months from the completion of the observations.

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.

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 10596

AGNs with Intermediate-mass Black Holes: A Test of the Black Hole-Bulge Paradigm

The recent progress in the study of central black holes in galactic nuclei has led to a general consensus that supermassive {10^6-10^9 solar mass} black holes are closely connected with the formation and evolutionary history of large galaxies, especially their bulge component. Two outstanding issues, however, remain unresolved. Can central black holes form in the absence of a bulge? And does the mass function of central black holes extend below 10^6 solar masses? Intermediate-mass black holes {10^4-10^6 solar masses}, if they exist, may offer important clues to the nature of the seeds of supermassive black holes. In a first systematic search using the Sloan Digital Sky Survey, we have recently discovered 19 Type 1 AGNs with candidate intermediate-mass black holes that reside in low-luminosity, presumably late-type host galaxies. Follow-up observations with Keck indicate that these objects obey the low-mass extension of the well-known correlation between black hole mass and bulge stellar velocity dispersion. However, very little is known about the host galaxies themselves, including the crucial question of whether they have bulges or not. We propose to obtain ACS/WFC images of this unique sample of AGNs in order to investigate the detailed structural properties of the host galaxies. We are particularly keen to determine whether the hosts contain bulges, and if so, where they lie on the fundamental plane of spheroids compared to the bulges of supermassive black holes. We will also be able to measure an accurate optical luminosity for the AGN, which is an essential ingredient to improve the current mass estimates.

ACS/WFC 10576

An ACS Imaging Survey of the Galaxies Hosting Strong Mg II Absorption

Strong MgII absorbers {with rest-frame absorption equivalent width W_MgII > 0.3 A} at redshift z < 1 are known to arise in extended gaseous halos around luminous galaxies. Detailed absorption line studies based on high-solution spectra of background quasars yield tight constraints on the metallicity, ionization state, and kinematics of the gaseous clouds. But whether they originate in gas accreted from surrounding satellite galaxies or outflows associated with active starburst in the host galaxies remains unclear. We have recently completed a search of the Sloan Digital Sky Survey data archive for strong MgII absorbers and identified over 1000 new systems that are previously unknown. A subset of these MgII absorbers with W_MgII > 1.8 A exhibit extreme kinematics with velocity widths {exceeding 200 km/s} in our follow-up echelle spectra. Their dynamics are consistent with various scenarios that include gas accretion {with speeds exceeding the virial velocity} and starburst outflows {possibly driven by recent merger events}. Independent of their exact nature, it is clear that strong MgII systems serve as signposts to galactic halos with extreme gas dynamics. Here we propose to conduct a snapshot survey of galaxies in the fields toward high-redshift quasars with known, strong MgII absorbers at 0.5 < z < 2. We plan to obtain high spatial-resolution ACS/WFC images of 60 fields to uncover galaxies fainter than L* at the redshifts of these absorbers and study their morphology. We will complement the HST observations with follow-up spectroscopic observations and IR images acquired at the Keck and Magellan Observatories to for redshift identifications and for measuring broad-band colors. We will investigate the correlation between absorption line kinematics and galaxy morphology. In particular, we will address whether on-going mergers is responsible for the extreme dynamics observed in MgII absorption based on their rest-frame ultraviolet morphology.

ACS/WFC 10526

Dynamics of the Polarization Structure of the Crab Nebula

The Crab Nebula is not a free expansion SNR. Rather, it is a pulsar wind nebula expanding from the inside out into a larger remnant of freely expanding ejecta. At the heart of this object is the Crab Pulsar and the region where the pulsar’s highly nonisotropic wind interacts with the larger synchtron nebula. HST and Chandra monitoring has shown this to be one of the most intricately structured and highly dynamical objects ever observed. In Cycle 12 we demonstrated our ability to use the polarization capabilities of the ACS to isolate physically discrete features within the Crab Synchrotron Nebula and accurately measure their polarization characteristics. These data provide a unique look at the physical structure in the heart of the Crab, adding a new dimension to past observations. Polarization provides extensive information about field geometries, the degree of disorder in the field, and particle pitch angle distributions. But one image of the Crab is like a single image of waves at the beach. It necessarily misses the point. In the Crab, the name of the game is “dynamics”. In this proposal we request time to monitor changes in the polarization structure of the Crab. This program will allow us to follow the changing polarization of features including relativistically moving wisps in the Crab Nebula. This is the only place in the sky where a dynamic relativistic plasma can be observed in sufficient detail to make such measurements possible, and the HST/ACS is the only instrument that we are likely to see in our careers capable of making the measurement. These observations will be an important addition to the already rich observational legacy of HST for what is arguably the most important single object in astrophysics.

ACS/HRC 10525

Characterizing the Near-UV Environment of M Dwarfs: Implications for Extrasolar Planetary Searches and Astrobiology

We propose SNAP observations with the ACS HRC PR200L prism, designed to measure the near ultraviolet emission in a sample of 107 nearby M dwarfs. The sample spans the mass range from 0.1 – 0.6 solar masses {temperature range 2200K – 4000K} where the UV energy distributions vary widely between active and inactive stars. The strength and distribution of this UV emission can have critical consequences for the atmospheres of attendant planets. Our proposed observations will provide desperately needed constraints on models of the habitability zone and the atmospheres of possible terrestrial planets orbiting M dwarf hosts, and will be used to sharpen TPF target selection. In addition, the NUV data will be used in conjunction with existing optical, FUV and X-ray data to constrain a new generation of M dwarf atmospheric models, and to explore unanswered questions regarding the dynamo generation and magnetic heating in these low-mass stars.

WFPC2 10511

An Edge-on Disk around a Brown Dwarf?

We have recently discovered a young brown dwarf in the Taurus star-forming region that exhibits several characteristics {very faint for its spectral type, forbidden emission lines, anomalous near-IR colors} that are often observed in stars occulted by edge-on circumstellar disks. We propose to determine if an edge-on disk is indeed present by obtaining high-resolution images of this brown dwarf with ACS/HRC on HST. If the disk is detected, we will constrain its physical properties, particularly its diameter, by fitting the images with the predictions of our models of brown dwarfs occulted by circumstellar disks. These observations could potentially provide the first direct measurement of the size of a disk around a brown dwarf, which would comprise a fundamental test of models for the formation of these objects {e.g., embryo ejection}.

ACS/WFC 10491

A Snapshot Survey of the most massive clusters of galaxies

We propose a snapshot survey of a sample of 124 high X-ray luminosity clusters in the redshift range 0.3-0.7. Similarly luminous clusters at these redshifts frequently exhibit strong gravitational lensing. The proposed observations will provide important constraints on the nature of the cluster mass distributions and a set of optically bright, lensed galaxies for further 8-10m spectroscopy. We acknowledge the broad community interest in this sample and waive our data rights for these observations.

ACS/WFC 10412

The host galaxies of dust-reddened quasars

We have used the 2MASS near-infrared and FIRST radio surveys, together with the Palomar Observatory Sky Survey plates to select a sample of dust-reddened, radio-intermediate quasars. We wish to use ACS to study the host galaxies of these quasars. The dust reddening of the quasars makes it possible to study the hosts at rest-frame optical-UV wavelengths much more easily than the hosts of normal quasars of similar bolometric luminosity. Our study will compare the hosts of our dust-reddened quasars to those of normal quasars from the HST archive to test the hypothesis that dust-reddened quasars are young objects, whose hosts still show morphological evidence of recent merger events which triggered the quasar.


The Formation and Evolution of Spirals: An ACS and WFPC2 Imaging Survey of Nearby Galaxies

Over 50% of galaxies in the local universe are spirals. Yet the star formation histories and evolution of this crucial population remain poorly understood. We propose to combine archival data with new ACS/WFC and WFPC2 observations of 11 galaxies, to tackle a comprehensive investigation of nearby spirals covering the entire spiral sequence. The new observations will fill a serious deficiency in HST’s legacy, and maximize the scientific return of existing HST data. The filter combination of UBVI, and Halpha is ideal for studying stellar populations, dust properties, and the ISM. Our immediate scientific objectives are: {i} to use the resolved cluster populations, both young massive clusters and ancient globular clusters as a chronometer, to understand how spirals assembled as a function of time; {ii} study the rapid disruption properties of young clusters; and {iii} understand dust distributions in spirals from pc to kpc scales. Each of these goals provides an important step towards charting the evolution of galaxies, and an essential baseline for interpreting the galaxy populations being surveyed in both the early and present universe. The resolution of our survey, which exploits the excellent imaging capabilities of HST’s two optical cameras, will enable us to understand the record of star cluster, and galaxy formation in a level of detail which is not possible for more distant systems. Finally, the proposed observations will provide a key to interpret an extensive, multiwavelength archive of space- and ground- based data at lower spatial resolution {SPITZER, CHANDRA, GALEX, NICMOS P alpha and H band imaging} for local spirals.

NIC1/NIC2/NIC3 10380

Cycle 13 NICMOS dark current, shading profile, and read noise monitoring program

The purpose of this proposal is to monitor the dark current, read noise, and shading profile for all three NICMOS detectors throughout the duration of Cycle 13. This proposal is an essentially unchanged continuation of PID 9993 which cover the duration of Cycle 12.


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

HSTARS: (None)

COMPLETED OPS REQUEST: 17581-0 – Genslew for Proposal 10114 – Slot 8 @ 294/1750z


                           SCHEDULED      SUCCESSFUL
Gsacq                  28                     28 

FGS Reacq                  15                     15
OBAD with Maneuver     84                     84


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