Status Report

NASA Hubble Space Telescope Daily Report #4387

By SpaceRef Editor
June 22, 2007
Filed under , ,
NASA Hubble Space Telescope Daily Report  #4387

Notice: For the foreseeable future, the daily reports may contain apparent discrepancies between some proposal descriptions and the listed instrument usage. This is due to the conversion of previously approved ACS WFC or HRC observations into WFPC2, or NICMOS observations subsequent to the loss of ACS CCD science capability in late January.


– Continuing to collect World Class Science

PERIOD COVERED: UT June 19, 2007 (DOY 170)


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 10927

The Weight-Watcher Program for Subdwarfs

We propose to use HST/FGS1r to measure five subdwarf spectroscopic binaries to determine masses for the components. Their metallicities, [Fe/H], range from -0.5 to -2.5, and their projected minimum separations range from 9 to 24 mas. These binaries are resolvable with HST/FGS1r but not any ground-based technique. Currently, there are only two subdwarf systems having any mass measurements. The proposed work will boost the total number of subdwarf systems with masses from two to seven, and allow us to construct the first mass-luminosity relation for low-metallicity stars.

NIC1/NIC2/NIC3 8794

NICMOS Post-SAA calibration – CR Persistence Part 5

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.

NIC3 10792

Quasars at Redshift z=6 and Early Star Formation History

We propose to observe four high-redshift quasars {z=6} in the NIR in order to estimate relative Fe/Mg abundances and the central black hole mass. The results of this study will critically constrain models of joint quasar and galaxy formation, early star formation, and the growth of supermassive black holes. Different time scales and yields for alpha-elements {like O or Mg} and for iron result into an iron enrichment delay of ~0.3 to 0.6 Gyr. Hence, despite the well-known complexity of the FeII emission line spectrum, the ratio iron/alpha – element is a potentially useful cosmological clock. The central black hole mass will be estimated based on a recently revised back hole mass – luminosity relationship. The time delay of the iron enrichment and the time required to form a supermassive black hole {logM>8 Msol, tau ~0.5Gyr} as evidenced by quasar activity will be used to date the beginning of the first intense star formation, marking the formation of the first massive galaxies that host luminous quasars, and to constrain the epoch when supermassive black holes start to grow by accretion.

NIC3 11072

Measuring the Physical Properties of the first two WASP transiting extrasolar planets

We have recently discovered the first two transiting extrasolar planets from the Wide Angle Search for Planets {WASP} project and confirmed both as planets using SOPHIE radial velocity measurements. Both WASP-1b and WASP-2b orbit about stars brighter than V=12, and are thus ideal targets for HST followup. WASP-1b is probably inflated in a manner similar to HD209458b but is in a closer orbit about the parent, which itself is the earliest-type parent star yet announced for a transiting extrasolar planet. At 0.03 AU from the parent star, WASP-2b is close to the minimum separation at which planets of this mass range are thought to survive. We request DD observations of WASP-1b and WASP- 2b, to constrain the masses and radii of both objects to a precision of a few tenths of a percent. Both parent stars have very similar brightnesses to the TrES-1 parent star, thus we will achieve equivalent photometric precision to previous successful observations of TrES-1b. As all further physical investigations {such as interior heating} depend on precise mass- and radius-determinations, this investigation is the essential next step in uncovering the physical characteristics of these planets and their parent stars. We have requested 12 orbits, though 9 orbits would provide the minimum acceptable coverage for our program. The consortium will formally announce the discoveries of WASP-1b and WASP-2b on Tuesday 26th September 2006. We ask that all material in this proposal be kept confidential until that date. We can supply the discovery paper on request after this date.

WFPC2 10890

Morphologies of the Most Extreme High-Redshift Mid-IR-Luminous Galaxies

The formative phase of the most massive galaxies may be extremely luminous, characterized by intense star- and AGN-formation. Till now, few such galaxies have been unambiguously identified at high redshift, restricting us to the study of low-redshift ultraluminous infrared galaxies as possible analogs. We have recently discovered a sample of objects which may indeed represent this early phase in galaxy formation, and are undertaking an extensive multiwavelength study of this population. These objects are bright at mid-IR wavelengths {F[24um]>0.8mJy}, but deep ground based imaging suggests extremely faint {and in some cases extended} optical counterparts {R~24-27}. Deep K-band images show barely resolved galaxies. Mid-infrared spectroscopy with Spitzer/IRS reveals that they have redshifts z ~ 2-2.5, suggesting bolometric luminosities ~10^{13-14}Lsun! We propose to obtain deep ACS F814W and NIC2 F160W images of these sources and their environs in order to determine kpc-scale morphologies and surface photometry for these galaxies. The proposed observations will help us determine whether these extreme objects are merging systems, massive obscured starbursts {with obscuration on kpc scales!} or very reddened {locally obscured} AGN hosted by intrinsically low-luminosity galaxies.

WFPC2 10915

ACS Nearby Galaxy Survey

Existing HST observations of nearby galaxies comprise a sparse and highly non-uniform archive, making comprehensive comparative studies among galaxies essentially impossible. We propose to secure HST’s lasting impact on the study of nearby galaxies by undertaking a systematic, complete, and carefully crafted imaging survey of ALL galaxies in the Local Universe outside the Local Group. The resulting images will allow unprecedented measurements of: {1} the star formation history {SFH} of a >100 Mpc^3 volume of the Universe with a time resolution of Delta[log{t}]=0.25; {2} correlations between spatially resolved SFHs and environment; {3} the structure and properties of thick disks and stellar halos; and {4} the color distributions, sizes, and specific frequencies of globular and disk clusters as a function of galaxy mass and environment. To reach these goals, we will use a combination of wide-field tiling and pointed deep imaging to obtain uniform data on all 72 galaxies within a volume-limited sample extending to ~3.5 Mpc, with an extension to the M81 group. For each galaxy, the wide-field imaging will cover out to ~1.5 times the optical radius and will reach photometric depths of at least 2 magnitudes below the tip of the red giant branch throughout the limits of the survey volume. One additional deep pointing per galaxy will reach SNR~10 for red clump stars, sufficient to recover the ancient SFH from the color-magnitude diagram. This proposal will produce photometric information for ~100 million stars {comparable to the number in the SDSS survey} and uniform multi- color images of half a square degree of sky. The resulting archive will establish the fundamental optical database for nearby galaxies, in preparation for the shift of high- resolution imaging to the near-infrared.


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

HSTARS: (None)


18103-1  – MSS/CSS Gyro2 Converged & Remove Gyro2 Test#39 for day 170

18054-0 – Preview KF Sun Vector Data via Telemetry Diags

                        SCHEDULED      SUCCESSFUL 
FGS GSacq                06                  06 
FGS REacq                08                  08 
OBAD with Maneuver       28                  28 



SpaceRef staff editor.