NASA Hubble Space Telescope Daily Status Report #4351

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.

HUBBLE SPACE TELESCOPE DAILY REPORT # 4351

– Continuing to collect World Class Science

PERIOD COVERED: UT April 27,28,29, 2007 (DOY 117,118,119)

OBSERVATIONS SCHEDULED

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.

WFPC2 11091

Hubble Heritage Observations of Arp 148

The Hubble Heritage team will use a single pointing of WFPC2 to obtain F450W, F555W, F656N, and F814W images of Arp 148 as part of a public release image.

WFPC2 11085

Europa in Eclipse: Tenuous Atmosphere, Electromagnetic Activity and Surface Luminescence HST Proposal 11085

We propose to image Europa during its orbital eclipse by Jupiter. This will form the basis of an investigation into the nature of the tenuous atmosphere, electromagnetic environment and surface material of Europa. We will compare the FUV oxygen line at 1356A to the optical line at 6300A and seek optical auroral hydrogen emission in Halpha. With broad continuum filters, we will search for optical emissions from other atmospheric constituents and for fluorescence of the surface material, arising from the very high level of incident energetic particle radiation. The high spatial resolution of ACS will allow us to fully resolve scales of interest and allow us to distinguish easily the different terrains on Europa’s surface. In particular we wish to compare luminesence in regions dominated by ice to those of potentially organic red material.

WFPC2 11083

The Structure, Formation and Evolution of Galactic Cores and Nuclei

A surprising result has emerged from the ACS Virgo Cluster Survey {ACSVCS}, a program to obtain ACS/WFC gz imaging for a large, unbiased sample of 100 early-type galaxies in the Virgo Cluster. On subarcsecond scales {i.e., <0.1"-1"}, the HST brightness profiles vary systematically from the brightest giants {which have nearly constant surface brightness cores} to the faintest dwarfs {which have compact stellar nuclei}. Remarkably, the fraction of galaxy mass contributed by the nuclei in the faint galaxies is identical to that contributed by supermassive black holes in the bright galaxies {0.2%}. These findings strongly suggest that a single mechanism is responsible for both types of Central Massive Object: most likely internally or externally modulated gas inflows that feed central black holes or lead to the formation of "nuclear star clusters". Understanding the history of gas accretion, star formation and chemical enrichment on subarcsecond scales has thus emerged as the single most pressing question in the study of nearby galactic nuclei, either active or quiescent. We propose an ambitious HST program {199 orbits} that constitutes the next, obvious step forward: high-resolution, ultraviolet {WFPC2/F255W} and infrared {NIC1/F160W} imaging for the complete ACSVCS sample. By capitalizing on HST's unique ability to provide high-resolution images with a sharp and stable PSF at UV and IR wavelengths, we will leverage the existing optical HST data to obtain the most complete picture currently possible for the history of star formation and chemical enrichment on these small scales. Equally important, this program will lead to a significant improvement in the measured structural parameters and density distributions for the stellar nuclei and the underlying galaxies, and provide a sensitive measure of "frosting" by young stars in the galaxy cores. By virtue of its superb image quality and stable PSF, NICMOS is the sole instrument capable of the IR observations proposed here. In the case of the WFPC2 observations, high-resolution UV imaging {< 0.1"} is a capability unique to HST, yet one that could be lost at any any time.

NIC1/NIC3 10924

Constraints on the Assembly and Dynamical Masses of z~2 Galaxies

We propose deep NICMOS/NIC2 F160W imaging of seven star-forming galaxies at z~2. These galaxies comprise an entirely unique sample, with not only redshifts measured from optical and near-IR spectra, but also SINFONI/VLT near-IR integral field spectroscopic measurements providing kinematic maps of H-alpha emission out to radii of >=10 kpc. We aim to determine the dynamical masses and evolutionary states of these systems, as part of the larger goal of understanding how mass is assembled in distant galaxies. In order to interpret our novel H-alpha integral field maps in terms of mass, we require detailed knowledge of the structural parameters of our target objects at rest-frame optical wavelengths and on ~1 kpc scales. We want to establish if the mass is distributed in a disk, bulge, or merging sub-units, and if we can detect tidal features associated with a merger. F160W imaging with NICMOS/NIC2 provides the perfect combination of sensitivity and resolution to address these questions, and arrive at the fundamental quantity: the dynamical mass.

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.

NIC3 10855

The Near-IR Spectra and Thermal Emission of Hot Jupiters

We propose to observe the brightest transiting exoplanet systems, HD 209458b and HD 189733b, during both primary eclipse {transit} and secondary eclipse {when the planet is behind the star}. A successful measurement would result in the spectral characterization of both dayside and nightside thermal emission. This, in turn, would result in several important determinations, including {1} the temperature of the dayside, {2} the temperature of the nightside, {3} the probable detection of water, {4} strong constraints on the presence or absence of clouds, and {5} constraints on models of atmospheric transport between the day and night sides. Our selected wavelength region of 1.4 to 2.4 microns includes the two most prominent predicted features {water} in models for hot Jupiter emission. For these observations, we propose to use the NICMOS 3 grism and selected narrow band filters in a carefully designed, differential observation intended to achieve a dynamic range of 10,000:1. Our proposed observations are uniquely enabled by HST, which alone has the combination of stability, sensitivity, wavelength coverage, and dynamic range to make these high- impact observations possible.

WFPC2 10786

Rotational state and composition of Pluto’s outer satellites

We propose an intricate set of observations aimed at discovering the rotational state of the newly discovered satellites of Pluto, S/2005 P1 and S/2005 P2. These observations will indicate if the satellites are in synchronous rotation or not. If they are not, then the observations will determine the rotational period or provide tight constraints on the amplitude. The other primary goal is to extend the wavelength coverage of the colors of the surface and allow us to constrain the surface compositions of both objects. From these data we will also be able to significantly improve the orbits of P1 and P2, improve the measurement of the bulk density of Charon, and search for albedo changes on the surface of Pluto.

WFPC2 10474

Shooting Stars: Looking for Direct Evidence of Massive Central Black Holes in Globular Clusters

We propose to make observations that directly test the proposition that globular clusters contain massive black holes. Our targets are the bulge globular clusters NGC 6388 and NGC 6441. These are probably among the most massive in the galaxy, but are understudied compared to more familiar objects such as M15. Our analysis suggests that these two clusters are the most likely to show unambiguous evidence for a central massive black hole if such things exist in globular clusters. The observations proposed will give us the first thorough kinematic and photometric studies of these two clusters. The combination of the two epochs will give us proper motions good to of order 6 km/s. In addition, they will provide us with the first good, deep, color-magnitude diagrams for these clusters. These diagrams will be used to investigate the make up of the stellar population in the clusters, to more firmly establish their distances, ages, and metallicities, and to search for a binary sequence.

FLIGHT OPERATIONS SUMMARY:

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

HSTARS: (None)

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

                       SCHEDULED      SUCCESSFUL 

FGS GSacq               17                   17 
FGS REacq               21                   21 
OBAD with Maneuver      60                   60 

SIGNIFICANT EVENTS:

Flash Report: HST Clock Rollover

The HST vehicle clock rollover occurred as expected on April 29, 2007 (DOY 119) at 18:06:30.769 GMT. Pre- and post-rollover operations were conducted nominally in accordance with the planned timeline and procedure. The first scheduled guide star acquisition after rollover occurred successfully at 119/20:16:33.