Status Report

NASA Hubble Space Telescope Daily Report # 4588

By SpaceRef Editor
April 14, 2008
Filed under , ,
NASA Hubble Space Telescope Daily Report # 4588


Continuing to collect World Class Science

PERIOD COVERED: UT April 11,12,13, 2008 (DOY 102,103,104)


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 images. Each observation will need its own CRMAP, as different SAA passages leave different imprints on the NICMOS detectors.

WFPC2 11312

The Local Cluster Substructure Survey {LoCuSS}: Deep Strong Lensing Observations with WFPC2

LoCuSS is a systematic and detailed investigation of the mass, substructure, and thermodynamics of 100 X-ray luminous galaxy clusters at 0.151} cluster samples. To complete the all-important high resolution imaging component of our survey, we request deep WFPC2 observations of 20 clusters through the F606W filter, for which wide-field weak-lensing data are already available from our Subaru imaging program. The combination of deep WFPC2 and Subaru data for these 20 clusters will enable us to achieve the science program approved by the Cycle 15 TAC.

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.

FGS 11211

An Astrometric Calibration of Population II Distance Indicators

In 2002 HST produced a highly precise parallax for RR Lyrae. That measurement resulted in an absolute magnitude, M{V}= 0.61+/-0.11, a useful result, judged by the over ten refereed citations each year since. It is, however, unsatisfactory to have the direct, parallax-based, distance scale of Population II variables based on a single star. We propose, therefore, to obtain the parallaxes of four additional RR Lyrae stars and two Population II Cepheids, or W Vir stars. The Population II Cepheids lie with the RR Lyrae stars on a common K-band Period-Luminosity relation. Using these parallaxes to inform that relationship, we anticipate a zero-point error of 0.04 magnitude. This result should greatly strengthen confidence in the Population II distance scale and increase our understanding of RR Lyrae star and Pop II Cepheid astrophysics.

FGS 11210

The Architecture of Exoplanetary Systems

Are all planetary systems coplanar? Concordance cosmogony makes that prediction. It is, however, a prediction of extrasolar planetary system architecture as yet untested by direct observation for main sequence stars other than the Sun. To provide such a test, we propose to carry out FGS astrometric studies on four stars hosting seven companions. Our understanding of the planet formation process will grow as we match not only system architecture, but formed planet mass and true distance from the primary with host star characteristics for a wide variety of host stars and exoplanet masses. We propose that a series of FGS astrometric observations with demonstrated 1 millisecond of arc per-observation precision can establish the degree of coplanarity and component true masses for four extrasolar systems: HD 202206 {brown dwarf+planet}; HD 128311 {planet+planet}, HD 160691 = mu Arae {planet+planet}, and HD 222404AB = gamma Cephei {planet+star}. In each case the companion is identified as such by assuming that the minimum mass is the actual mass. For the last target, a known stellar binary system, the companion orbit is stable only if coplanar with the AB binary orbit.

NIC3 11195

Morphologies of the Most Extreme High-Redshift Mid-IR-luminous Galaxies II: The `Bump’ Sources

The formative phase of some 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, and thus far we have been restricted to studying the 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 optically extremely faint {R>26} but nevertheless bright at mid-infrared wavelengths {F[24um] > 0.5 mJy}. Mid-infrared spectroscopy with Spitzer/IRS reveals that they have redshifts z~2, implying luminosities ~1E13 Lsun. Their mid-IR SEDs fall into two broad, perhaps overlapping, categories. Sources with brighter F[24um] exhibit power-law SEDs and SiO absorption features in their mid-IR spectra characteristic of AGN, whereas those with fainter F[24um] show a “bump” characteristic of the redshifted 1.6um peak from a stellar population, and PAH emission characteristic of starformation. We have begun obtaining HST images of the brighter sources in Cycle 15 to obtain identifications and determine kpc-scale morphologies for these galaxies. Here, we aim to target the second class {the “bump” sources} with the goal of determining if these constitute morphologically different objects, or simply a “low-AGN” state of the brighter class. The proposed observations will help us determine whether these 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 11178

Probing Solar System History with Orbits, Masses, and Colors of Transneptunian Binaries

The recent discovery of numerous transneptunian binaries {TNBs} opens a window into dynamical conditions in the protoplanetary disk where they formed as well as the history of subsequent events which sculpted the outer Solar System and emplaced them onto their present day heliocentric orbits. To date, at least 47 TNBs have been discovered, but only about a dozen have had their mutual orbits and separate colors determined, frustrating their use to investigate numerous important scientific questions. The current shortage of data especially cripples scientific investigations requiring statistical comparisons among the ensemble characteristics. We propose to obtain sufficient astrometry and photometry of 23 TNBs to compute their mutual orbits and system masses and to determine separate primary and secondary colors, roughly tripling the sample for which this information is known, as well as extending it to include systems of two near-equal size bodies. To make the most efficient possible use of HST, we will use a Monte Carlo technique to optimally schedule our observations.

NIC2/NIC1/NIC3 11159

The True Galactic Bulge Luminosity Function

We propose to obtain second epoch imaging of the deep Galactic bulge field observed using NICMOS by Zoccali et al. (2000). The bulge luminosity and mass function suffered from 30-50% contamination by foreground disk stars, which was impossible to correct for in the original study. Revisiting the field after 9 years, we propose to segregate the foreground disk stars because they have large transverse velocities, thus revealing the luminosity function of Galactic bulge low mass stars to near the hydrogen burning limit. The slope of the mass function has implications for galaxy formation and for understanding the nature of microlensing in the Galactic bulge.

NIC3 11149

Characterizing the Stellar Populations in Lyman-Alpha Emitters and Lyman Break Galaxies at 5.7

The epoch of reionization marks a major phase transition of the Universe, during which the intergalactic space became transparent to UV photons. Determining when this occurred and the physical processes involved represents the latest frontier in observational cosmology. Over the last few years, searches have intensified to identify the population of high-redshift (z>6) galaxies that might be responsible for this process, but the progress is hampered partly by the difficulty of obtaining physical information (stellar mass, age, star formation rate/history) for individual sources. This is because the number of z>6 galaxies that have both secure spectroscopic redshifts and high-quality infrared photometry (especially with Spitzer/IRAC) is still fairly small. Considering that only several photometric points are available per source, and that many model SEDs are highly degenerate, it is crucial to obtain as many observational constraints as possible for each source to ensure the validity of SED modeling. To better understand the physical properties of high-redshift galaxies, we propose here to conduct HST/NICMOS (72 orbits) and Spitzer/IRAC (102 hours) imaging of spectroscopically confirmed, bright (z<26 mag (AB)) Ly-alpha emitters (LAEs) and Lyman-break galaxies (LBGs) at 5.76 as suggested recently? (2) Is Ly-alpha emission systematically suppressed at z>6 with respect to continuum emission? (i.e., are we reaching the epoch of incomplete reionization?), and (3) Do we see any sign of abnormally young stellar population in any of the z>6 galaxies?

NIC2 11143

NICMOS imaging of submillimeter galaxies with CO and PAH redshifts

We propose to obtain F110W and F160W imaging of 10 z~2.4 submillimeter galaxies {SMGs} whose optical redshifts have been confirmed by the detection of millimeter CO and/or mid- infrared PAH emission. With the 4000A break falling within/between the two imaging filters, we will be able to study these sources’ spatially resolved stellar populations {modulo extinction} in the rest-frame optical. SMGs’ large luminosities appear to be due largely to merger-triggered starbursts; high-resolution NICMOS imaging will help us understand the stellar masses, mass ratios, and other properties of the merger progenitors, valuable information in the effort to model the mass assembly history of the universe.

NIC1/NIC2 11139

NICMOS Observations of the Microquasar GRS 1758-258

The galactic black hole candidate GRS 1758-258 is normally one of the brightest persistent gamma-ray sources in the vicinity of the galactic center. It is a microquasar with relativistic radio jets emanating from a central variable source. Microquasars are excellent nearby test laboratories for studying the complex accretion and outflow processes that take place near black hole horizons. Despite an accurate location provided by Chandra and the VLA and over a decade of careful ground-based studies, the optical/infrared counterpart to GRS 1758-258 remains unknown. A stellar counterpart is expected, but the current candidates are all more than 2 sigma from the center of the error circle. The ground-based infrared flux limits are also right at the values expected for the synchrotron emission from the outflow from the black hole, and possibly for the emission from the accretion disk. This leaves open the question as to what is powering this very energetic persistent source. Here we propose to use NICMOS to perform broad-band imaging of the GRS 1758- 258 error box. These images will be more than three magnitudes more sensitive than the current ground-based ones. The resulting spectra will reveal the thermal/non- thermal nature of the sources in the region of the error box, and the high spatial resolution images may reveal a jet structure. We propose to perform three visits of two orbits each spanning the suggested 18.45 day binary orbital period of the system: a correct counterpart identification should be confirmed by its variability. We will also aim to support the HST observations with X- and gamma-ray observations using Swift or INTEGRAL, and with longer wavelength observations from the ground.

NIC3 11120

A Paschen-Alpha Study of Massive Stars and the ISM in the Galactic Center

The Galactic center (GC) is a unique site for a detailed study of a multitude of complex astrophysical phenomena, which may be common to nuclear regions of many galaxies. Observable at resolutions unapproachable in other galaxies, the GC provides an unparalleled opportunity to improve our understanding of the interrelationships of massive stars, young stellar clusters, warm and hot ionized gases, molecular clouds, large scale magnetic fields, and black holes. We propose the first large-scale hydrogen Paschen alpha line survey of the GC using NICMOS on the Hubble Space Telescope. This survey will lead to a high resolution and high sensitivity map of the Paschen alpha line emission in addition to a map of foreground extinction, made by comparing Paschen alpha to radio emission. This survey of the inner 75 pc of the Galaxy will provide an unprecedented and complete search for sites of massive star formation. In particular, we will be able to (1) uncover the distribution of young massive stars in this region, (2) locate the surfaces of adjacent molecular clouds, (3) determine important physical parameters of the ionized gas, (4) identify compact and ultra-compact HII regions throughout the GC. When combined with existing Chandra and Spitzer surveys as well as a wealth of other multi-wavelength observations, the results will allow us to address such questions as where and how massive stars form, how stellar clusters are disrupted, how massive stars shape and heat the surrounding medium, and how various phases of this medium are interspersed.

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 11099

A “silver bullet” for the sources of reionization

Recent discoveries of z>6 galaxies have given us the first glimpse of the Universe shortly after the era of reionization. The questions arose whether these first galaxies can be made responsible for the reionization process, and how long did it last. Neither observations nor theory provide a clean answer. In particular observations give results that are barely mutually consistent and need to be further tested. Observing high redshift (z>7) sources is in general difficult, mostly due to the high luminosity distance to these objects, and partly due to the lower expected stellar masses compared to objects at moderate redshifts.

We propose to use one of the most massive, merging cluster 1E0657-56 (z=0.295) as a cosmic telescopes to efficiently probe the high-redshift universe. The gravitational potential well of this cluster provides several magnitudes of magnification, enabling study of intrinsically lower luminosity galaxies.As we discuss in the proposal, due to its highly elongated mass distribution and ideal redshift the bullet cluster is a prime candidate for this study. We propose deep NICMOS and WFPC2 observations; with much reduced observing time compared to e.g. NICMOS UDF we expect an order of magnitude more (~5 candidates) z>7 objects. They will also likely be multiply imaged, and since the geometry of images depends upon the redshift, we will be able to confirm their nature, thereby not requiring (often prohibitive at these magnitudes) spectroscopic follow-up. This will enable us to count high-redshift sources and constrain their luminosity function; a task made possible with the help of gravitational lensing even in the pre-JWST era.


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


11249 – GSacq(2,1,2) failed to RGA control. @ 102/1514z

During LOS GSaq(2,1,2) scheduled at 102/15:14:50 failed to RGA control. The GSacq failed due to receiving stop flag QF2STOPF on FGS 2. The Map at 15:23:32 showed errors of V1=17.15, V2=9.04, V3=3.75, and RSS=19.75.

11252 – OBAD Failed Identification (ESB 1902) @ 104/1625z

At Acquisition of Signal (104/16:25:46) received three (3) 486 STB ESB 1902 “OBAD Failed ID” messages. Vehicle was in RGA control, M2G mode with OBAD flag mnemonics showing GOBSTAT=255 (Attitude Determination Error) and GCHACL09=1 or (Failed State). OBAD Map at 15:40:16 showed errors of: V1 -32245.59, V2 6342.19, V3 -51499.65, RSS 61091.86 arc-seconds. The GSAcquisition at 15:32:59 was not attempted as the #44 commands had not updated. Ops Request 17543-2 was successfully executed and copies of the dump for tables 369 & 370 are attached. Awaiting next available engineering data dump to perform further analysis.

11253 – GSAcq (2,3,3) results in RGA Control @ 104/1625z

At Acquisition of Signal (104/16:25:46) GSAcq (2,3,3) scheduled from (15:32:59-15:40:16) had not attempted due to both pre-acquisition OBAD’s failing. GSAcq #44 commands did not update. OBAD #1 RSS error was 61102.55 arc-seconds. OBAD #2 RSS error was 56101.50 arc-seconds. OBAD Map RSS error was 61091.86 arc-seconds.


17543-2 – Dump OBAD tables after failed OBAD (Generic) @ 104/1643z


                        SCHEDULED      SUCCESSFUL

FGS GSacq               23                   21
FGS REacq               11                  11
OBAD with Maneuver      70                   68


Flash Report: FGS ITS Test

The ITS tests scheduled from 105:02:42 – 105:06:00 performed as expected. The first ITS test was monitored in real time and no anomalous behavior was seen. The other ITS tests occurred in ZOEs and the data will be looked at when it is merged. There were no problems indicated in telemetry when telemetry was reacquired after the tests were performed. The subsequent guide star acquisitions have all been successful.

All SSR ENG data was dumped at 105/0749z

SpaceRef staff editor.