NASA Hubble Space Telescope Daily Status Report #4658
HUBBLE SPACE TELESCOPE DAILY REPORT #4658
Continuing to collect World Class Science
PERIOD COVERED: 5am July 22 – 5am July 23, 2008 (DOY 204/0900z-205/0900z)
OBSERVATIONS SCHEDULED
FGS 11212
Filling the Period Gap for Massive Binaries
The current census of binaries among the massive O-type stars is seriously incomplete for systems in the period range from years to millennia because the radial velocity variations are too small and the angular separations too close for easy detection. Here we propose to discover binaries in this observational gap through a Faint Guidance Sensor SNAP survey of relatively bright targets listed in the Galactic O Star Catalog. Our primary goal is to determine the binary frequency among those in the cluster/association, field, and runaway groups. The results will help us assess the role of binaries in massive star formation and in the processes that lead to the ejection of massive stars from their natal clusters. The program will also lead to the identification of new, close binaries that will be targets of long term spectroscopic and high angular resolution observations to determine their masses and distances. The results will also be important for the interpretation of the spectra of suspected and newly identified binary and multiple systems.
NIC1/NIC2/NIC3 8795
NICMOS Post-SAA Calibration – CR Persistence Part 6
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 i mages. Each observation will need its own CRMAP, as different SAA passages leave different imprints on the NICMOS detectors.
NIC2 11135
Extreme Makeovers: Tracing the Transformation of Massive Galaxies at z~2.5
To obtain a full spectroscopic census of the universe at z~2.5 we have conducted a near-infrared spectroscopic survey for K-selected galaxies. We found that, in contrast to the local universe, massive high-redshift galaxies span a wide range of properties, varying from (dusty) star burst to “red and dead” galaxies. This may imply that massive galaxies transform from star-forming to quiescent galaxies in the targeted redshift range. To understand whether the 9 quiescent galaxies in our sample are the progenitors of local elliptical, we are observing them in the current cycle with NIC2. For cycle 16 we propose to complete our sample of massive z~2.5 galaxies and image the remaining 10 galaxies, which all have emission lines. Based on emission-line diagnostics, 6 of these galaxies are identified as star-forming objects and 4 harbor an active galactic nucleus. The goals are to 1) determine whether star formation in massive z~2.5 galaxies takes place in disks or is triggered by merger activity, 2) derive the contribution of AGNs to the rest-frame optical emission, and 3) test whether the morphologies are consistent with the idea that the star-forming galaxies, AGNs, and quiescent galaxies represent subsequent phases of an evolutionary sequence. The combination of both programs will provide the first morphological study of a spectroscopically confirmed massive galaxy sample at z~2.5.
NIC3 11545
A NICMOS Survey of Newly-Discovered Young Massive Clusters
We are on the cusp of a revolution in massive star research triggered by 2MASS and Spitzer/GLIMPSE, and now is the ideal time to capitalize on these projects by performing the first survey of massive stars in young stellar clusters throughout the Galactic plane. A search of the 2MASS and GLIMPSE surveys has produced over 450 newly-identified massive stellar cluster candidates in the Galactic plane which are hidden from our view at optical wavelengths due to extinction. Here we propose a program of 29 orbits to image the most promising candidate clusters in broad and narrow band filters using HST/NICMOS. We will be complementing these observations with approved Spitzer and Chandra programs, numerous approved and planned ground-based spectroscopic observations, and state-of-the-art modeling. We expect to substantially increase the numbers of massive stars known in the Galaxy, including main sequence OB stars and post-main sequence stars in the Red Supergiant, Luminous Blue Variable and Wolf-Rayet stages. Ultimately, this program will address many of the fundamental topics in astrophysics: the slope to the initial mass function (IMF), an upper-limit to the masses of stars, the formation and evolution of the most massive stars, gamma-ray burst (GRB) progenitors, the chemical enrichment of the interstellar medium, and nature of the first stars in the Universe.
WFPC2 11113
Binaries in the Kuiper Belt: Probes of Solar System Formation and Evolution
The discovery of binaries in the Kuiper Belt and related small body populations is powering a revolutionary step forward in the study of this remote region. Three quarters of the known binaries in the Kuiper Belt have been discovered with HST, most by our snapshot surveys. The statistics derived from this work are beginning to yield surprising and unexpected results. We have found a strong concentration of binaries among low-inclination Classicals, a possible size cutoff to binaries among the Centaurs, an apparent preference for nearly equal mass binaries, and a strong increase in the number of binaries at small separations. We propose to continue this successful program in Cycle 16; we expect to discover at least 13 new binary systems, targeted to subgroups where these discoveries can have the greatest impact.
WFPC2 11156
Monitoring Active Atmospheres on Uranus and Neptune
We propose Snapshot observations of Uranus and Neptune to monitor changes in their atmospheres on time scales of weeks and months. Uranus equinox is only months away, in December 2007. Hubble Space Telescope observations during the past several years {Hammel et al. 2005, Icarus 175, 284 and references therein} have revealed strongly wavelength- dependent latitudinal structure, the presence of numerous visible-wavelength cloud features in the northern hemisphere, at least one very long-lived discrete cloud in the southern hemisphere, and in 2006 the first dark spot ever seen on Uranus. Long-term ground-based observations {Lockwood and Jerzekiewicz, 2006, Icarus 180, 442; Hammel and Lockwood 2007, Icarus 186, 291} reveal seasonal brightness changes whose origins are not well understood. Recent near- IR images of Neptune obtained using adaptive optics on the Keck Telescope, together with HST observations {Sromovsky et al. 2003, Icarus 163, 256 and references therein} which include previous Snapshot programs {GO 8634, 10170, 10534} show a general increase in activity at south temperate latitudes until 2004, when Neptune returned to a rather Voyager-like appearance. Further Snapshot observations of these two dynamic planets will elucidate the nature of long-term changes in their zonal atmospheric bands and clarify the processes of formation, evolution, and dissipation of discrete albedo features.
WFPC2 11218
Snapshot Survey for Planetary Nebulae in Globular Clusters of the Local Group
Planetary nebulae {PNe} in globular clusters {GCs} raise a number of interesting issues related to stellar and galactic evolution. The number of PNe known in Milky Way GCs, 4, is surprisingly low if one assumes that all stars pass through a PN stage. However, it is likely that the remnants of stars now evolving in Galactic GCs leave the AGB so slowly that any ejected nebula dissipates long before the star becomes hot enough to ionize it. Thus there should not be ANY PNe in Milky Way GCs–but there are four! It has been suggested that these PNe are the result of mergers of binary stars within GCs, i.e., that they are descendants of blue stragglers. The frequency of occurrence of PNe in external galaxies poses more questions, because it shows a range of almost an order of magnitude. I propose a Snapshot survey aimed at discovering PNe in the GC systems of Local Group galaxies more distant than the Magellanic Clouds. These clusters, some of which may be much younger than their counterparts in the Milky Way, might contain many more PNe than those of our own galaxy. I will use the standard technique of emission-line and continuum imaging, which easily discloses PNe.
WFPC2 11235
HST NICMOS Survey of the Nuclear Regions 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 NICMOS NIC2 imaging of the nuclear regions 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 and resolution of NICMOS NIC2 on HST enables a unique opportunity to study the detailed structure of the nuclear regions, where dust obscuration may mask star clusters, AGN and additional nuclei from optical view, with a resolution significantly higher than possible with Spitzer IRAC. This survey thus provides a crucial component to our study of the dynamics and evolution of IR galaxies presently underway with Wide-Field, HST ACS/WFC and Spitzer IRAC observations of these 88 galaxies. Imaging will be done with the F160W filter {H-band} to examine as a function of both luminosity and merger stage {i} the luminosity and distribution of embedded star clusters, {ii} the presence of optically obscured AGN and nuclei, {iii} the correlation between the distribution of 1.6 micron emission and the mid-IR emission as detected by Spitzer IRAC, {iv} the evidence of bars or bridges that may funnel fuel into the nuclear region, and {v} the ages of star clusters for which photometry is available via ACS/WFC observations. The NICMOS data, combined with the HST ACS, Spitzer, and GALEX observations of this sample, will result in the most comprehensive study of merging and interacting galaxies to date.
WFPC2/NIC3/ACS/SBC 11144
Building on the Significant NICMOS Investment in GOODS: A Bright, Wide-Area Search for z>=7 Galaxies
One of the most exciting frontiers in observational cosmology has been to trace the buildup and evolution of galaxies from very early times. While hierarchical theory teaches us that the star formation rate in galaxies likely starts out small and builds up gradually, only recently has it been possible to see evidence for this observationally through the evolution of the LF from z~6 to z~3. Establishing that this build up occurs from even earlier times {z~7-8} has been difficult, however, due to the small size of current high-redshift z~7-8 samples — now numbering in the range of ~4-10 sources. Expanding the size of these samples is absolutely essential, if we are to push current studies of galaxy buildup back to even earlier times. Fortunately, we should soon be able to do so, thanks to ~50 arcmin**2 of deep {26.9 AB mag at 5 sigma} NICMOS 1.6 micron data that will be available over the two ACS GOODS fields as a result of one recent 180-orbit ACS backup program and a smaller program. These data will nearly triple the deep near-IR imaging currently available and represent a significant resource for finding and characterizing the brightest high-redshift sources — since high-redshift candidates can be easily identified in these data from their red z-H colors. Unfortunately, the red z-H colors of these candidates are not sufficient to determine that these sources are at z>=7, and it is important also to have deep photometry at 1.1 microns. To obtain this crucial information, we propose to follow up each of these z-H dropouts with NICMOS at 1.1 microns to determine which are at high redshift and thus significantly expand our sample of luminous, z>=7 galaxies. Since preliminary studies indicate that these candidates occur in only 30% of the NIC3 fields, our follow-up strategy is ~3 times as efficient as without this pre-selection and 9 times as efficient as a search in a field with no pre- existing data. In total, we expect to identify ~8 luminous z-dropouts and possibly ~2 z~10 J- dropouts as a result of this program, more than tripling the number currently known. The increased sample sizes are important if we are to solidify current conclusions about galaxy buildup and the evolution of the LF from z~8. In addition to the high redshift science, these deep 1.1 micron data would have significant value for many diverse endeavors, including {1} improving our constraints on the stellar mass density at z~7-10 and {2} doubling the number of galaxies at z~6 for which we can estimate dust obscuration.
FLIGHT OPERATIONS SUMMARY:
Significant Spacecraft Anomalies: (The following are preliminary reports of potential non-nominal performance that will be investigated.)
HSTARS:
11404 Loss of Lock in level 2 SAA @ 204/1237z.
Following a successful REACQ(1,3,1) at 11:57:01z, there was a loss of lock @12:37:55z while in SAA2 with QF3STOPF and QSTOP flags set & take data flag went down. TERM EXP scheduled @12:58:20z. Observation affected: NICMOS #30, proposal 08795.
11405 REACQ(2,1,2) fine lock backup on FGS 2 only during LOS @ 204/1650z.
QF1STOPF and QSTOP flags set on FGS 1. Observation affected: WFPC 75 TO 76, ACS 2, NICMOS 32; proposal 11144
COMPLETED OPS REQUEST: (None)
COMPLETED OPS NOTES: (None)
SCHEDULED SUCCESSFUL
FGS GSacq 7 7
FGS REacq 7 7
OBAD with Maneuver 28 28
SIGNIFICANT EVENTS: (None)
