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Daily Report #4746
HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science
DAILY REPORT****** #4746 PERIOD COVERED: 5am November 26 - 5am December 1, 2008 (DOY ************************** 331/1000z-336/1000z) OBSERVATIONS SCHEDULED WFPC2/ACS/SBC 11957 Hubble Investigation of Asteroid 21 Lutetia in Support of the Rosetta Mission Flyby The Rosetta mission is gearing up for a flyby encounter with the large, main belt asteroid 21 Lutetia, with closest approach on 2010 June 10. The next opposition, on 2008 December 1, is our last opportunity to make observations in time to affect the planning of the Rosetta program. We request a total of 5 orbits of Hubble observing time (2 using ACS/SBC and 3 using WFPC2) to characterize the UV albedo of Lutetia, to search for any dust debris near the main body, and to perform a deep search for companions. Even one orbit of Hubble time would provide valuable data for planning the Rosetta-Alice ultraviolet spectrometer observations, and 2 orbits are sufficient to characterize the far-UV albedo, but a 5-orbit program provides a richer scientific investigation with potentially much broader implications, both scientifically and for Rosetta planning. WFPC2 11956 Hubble Heritage: Side B We propose a program of 39 orbits to observe 6 targets with WFPC2 following a successful return to science using side B electronics. These observations will be used for Hubble Heritage releases in the months leading up to servicing mission 4. Because of launch delays, our reserve of releasable images is growing dangerously slim. We are proposing here to replenish one of our important lines of communication with the public. We have carefully chosen targets that can efficiently use single pointings of WFPC2 to obtain images of visually striking and astrophysically interesting targets. Observations will reach high S/N and will be dithered and subsampled to improve the resolution and pixel scale to near ACS/WFC3 quality at a modest cost in exposure time. Most of the observations will schedule in the interim between a return to science and the availability of new science proposals that may be selected in response to an interim call for proposals. FGS 11943 Binaries at the Extremes of the H-R Diagram We propose to use HST/Fine Guidance Sensor 1r to survey for binaries among some of the most massive, least massive, and oldest stars in our part of the Galaxy. FGS allows us to spatially resolve binary systems that are too faint for ground-based, speckle or optical long baseline interferometry, and too close to resolve with AO. We propose a SNAP-style program of single orbit FGS TRANS mode observations of very massive stars in the cluster NGC 3603, luminous blue variables, nearby low mass main sequence stars, cool subdwarf stars, and white dwarfs. These observations will help us to (1) identify systems suitable for followup studies for mass determination, (2) study the role of binaries in stellar birth and in advanced evolutionary states, (3) explore the fundamental properties of stars near the main sequence-brown dwarf boundary, (4) understand the role of binaries for X-ray bright systems, (5) find binaries among ancient and nearby subdwarf stars, and (6) help calibrate the white dwarf mass - radius relation. WFPC2 11796 WFPC2 Cycle 16 Decontaminations and Associated Observations This proposal is for the WFPC2 decons. Also included are instrument monitors tied to decons: photometric stability check, focus monitor, pre- and post-decon internals (bias, intflats, kspots, & darks), UV throughput check, VISFLAT sweep, and internal UV flat check. FGS 11789 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. ACS/SBC 11681 A Search for Ultraviolet Emission Filaments in Cool Core Clusters We propose to use ACS SBC imaging to seek ultraviolet CIV emission filaments in clusters of galaxies exhibiting strong cool-core X-ray emission and optical line emission filaments. These short observations are crafted to test thermal conduction models for the filament excitation, and can significantly impact our understanding of the overall physical processes dominant in the galaxy cluster ISM. WFPC2 11289 SL2S: The Strong Lensing Legacy Survey Recent systematic surveys of strong galaxy-galaxy lenses {CLASS, SLACS, GOODS, etc.} are producing spectacular results for galaxy masses roughly below a transition mass M~10^13 Mo. The observed lens properties and their evolution up to z~0.2, consistent with numerical simulations, can be described by isothermal elliptical potentials. In contrast, modeling of giant arcs in X-ray luminous clusters {halo masses M ~10^13 Mo} favors NFW mass profiles, suggesting that dark matter halos are not significantly affected by baryon cooling. Until recently, lensing surveys were neither deep nor extended enough to probe the intermediate mass density regime, which is fundamental for understanding the assembly of structures. The CFHT Legacy Survey now covers 125 square degrees, and thus offers a large reservoir of strong lenses probing a large range of mass densities up to z~1. We have extracted a list of 150 strong lenses using the most recent CFHTLS data release via automated procedures. Following our first SNAPSHOT proposal in cycle 15, we propose to continue the Hubble follow-up targeting a larger list of 130 lensing candidates. These are intermediate mass range candidates {between galaxies and clusters} that are selected in the redshift range of 0.2-1 with no a priori X-ray selection. The HST resolution is necessary for confirming the lensing candidates, accurate modeling of the lenses, and probing the total mass concentration in galaxy groups up to z~1 with the largest unbiased sample available to date. ACS/SBC/WFPC2 11230 HST FUV Observations of Brightest Cluster Galaxies: The Role of Star Formation in Cooling Flows and BCG Evolution The intracluster medium (ICM) now appears to be a very dynamic place where heating and cooling processes vie for dominance and an uneasy equilibrium is maintained. Since these same processes may operate during the process of galaxy formation, the centers of clusters of galaxies provide low redshift laboratories for studying the critical processes involved in galaxy formation and black hole growth. At the present time, the main questions are (1) How much gas is cooling out of the ICM? (2) How much star formation is ongoing? (3) What is the impact of the gas and star formation on the central BCG? In order to measure the current star formation in BCGs we have undertaken a program of Spitzer IRAC and MIPS observations. We are in process of obtaining observations of a sample of Brightest Cluster Galaxies in 70 clusters selected from the ROSAT all sky survey. In about 25% of the sources observed so far, we detect a mid-IR excess which we attribute to dust heated by star formation. We propose to obtain ACS/SBC observations of the Lyman Alpha emission line and the adjacent FUV continuum in 7 BCGs which are in cooling core clusters of galaxies and have a large mid-IR excess. We also propose WFPC2 F606W observations of the two clusters without high resolution imaging to allow us to image the dust on the same scale as the Far UV continuum. The FUV will allow us to confirm the presence of ongoing star formation in these BCGs and will allow us to rule out an AGN as the dominant contributor to the mid-IR. The morphology and spatial extent of the young stars and the heated dust and CO will constrain the spatial scale over which star formation occurs and thus where the cooling gas is deposited. The combination of our FUV and IR observations will allow us to estimate the star formation rates which must balance the rate at which cold gas is deposited in the BCG. Our proposed FUV observations will produce unique information about the cooling gas, the true mass accretion rates, and the star formation rates in BCGs and its effect on the galaxy. WFPC2 11201 Systemic and Internal Motions of the Magellanic Clouds: Third Epoch Images In Cycles 11 and 13 we obtained two epochs of ACS/HRC data for fields in the Magellanic Clouds centered on background quasars. We used these data to determine the proper motions of the LMC and SMC to better than 5% and 15% respectively. These are by far the best determinations of the proper motions of these two galaxies. The results have a number of unexpected implications for the Milky Way-LMC-SMC system. The implied three-dimensional velocities are larger than previously believed, and are not much less than the escape velocity in a standard 10^12 solar mass Milky Way dark halo. Orbit calculations suggest the Clouds may not be bound to the Milky Way or may just be on their first passage, both of which would be unexpected in view of traditional interpretations of the Magellanic Stream. Alternatively, the Milky Way dark halo may be a factor of two more massive than previously believed, which would be surprising in view of other observational constraints. Also, the relative velocity between the LMC and SMC is larger than expected, leaving open the possibility that the Clouds may not be bound to each other. To further verify and refine our results we now request an epoch of WFPC2/PC data for the fields centered on 40 quasars that have at least one epoch of ACS imaging. We request execution in snapshot mode, as in our previous programs, to ensure the most efficient use of HST resources. A third epoch of data of these fields will provide crucial information to verify that there are no residual systematic effects in our previous measurements. More importantly, it will increase the time baseline from 2 to 5 yrs and will increase the number of fields with at least two epochs of data. This will reduce our uncertainties correspondingly, so that we can better address whether the Clouds are indeed bound to each other and to the Milky Way. It will also allow us to constrain the internal motions of various populations within the Clouds, and will allow us to determine a distance to the LMC using rotational parallax. ACS/SBC 11151 Evaluating the Role of Photoevaporation of Protoplanetary Disk Dispersal Emission produced by accretion onto the central star leads to photoevaporation, which may play a fundamental role in disk dispersal. Models of disk photoevaporation by the central star are challenged by two potential problems: the emission produced by accretion will be substantially weaker for low-mass stars, and photoevaporation must continue as accretion slows. Existing FUV spectra of CTTSs are biased to solar-mass stars with high accretion rates, and are therefore insufficient to address these problems. We propose use HST/ACS SBC PR130L to obtain FUV spectra of WTTSs and of CTTSs at low masses and mass accretion rates to provide crucial data to evaluate photoevaporation models. We will estimate the FUV and EUV luminosities of low-mass CTTSs with small mass accretion rates, CTTSs with transition disks and slowed accretion, and of magnetically-active WTTSs. WFPC2 11130 AGNs with Intermediate-mass Black Holes: Testing the Black Hole-Bulge Paradigm, Part II 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 {10^6 solar masses}, if they exist, may offer important clues to the nature of the seeds of supermassive black holes. Using the SDSS, our group has successfully uncovered a new population of AGNs with intermediate-mass black holes that reside in low-luminosity galaxies. However, very little is known about the detailed morphologies or structural parameters of the host galaxies themselves, including the crucial question of whether they have bulges or not. Surprisingly, the majority of the targets of our Cycle 14 pilot program have structural properties similar to dwarf elliptical galaxies. The statistics from this initial study, however, are really too sparse to reach definitive conclusions on this important new class of black holes. We wish to extend this study to a larger sample, by using the Snapshot mode to obtain WFPC2 F814W images from a parent sample of 175 AGNs with intermediate- mass black holes selected from our final SDSS search. We are particularly keen to determine whether the hosts contain bulges, and if so, how the fundamental plane properties of the host depend on the mass of their central black holes. We will also investigate the environment of this unique class of AGNs. 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 11103 A Snapshot Survey of The Most Massive Clusters of Galaxies We propose the continuation of our highly successful SNAPshot survey of a sample of 125 very X-ray luminous clusters in the redshift range 0.3-0.7. As demonstrated by the 25 snapshots obtained so far in Cycle14 and Cycle15 these systems frequently exhibit strong gravitational lensing as well as spectacular examples of violent galaxy interactions. The proposed observations will provide important constraints on the cluster mass distributions, the physical nature of galaxy-galaxy and galaxy-gas interactions in cluster cores, and a set of optically bright, lensed galaxies for further 8-10m spectroscopy. All of our primary science goals require only the detection and characterization of high-surface-brightness features and are thus achievable even at the reduced sensitivity of WFPC2. Because of their high redshift and thus compact angular scale our target clusters are less adversely affected by the smaller field of view of WFPC2 than more nearby systems. Acknowledging the broad community interest in this sample we waive our data rights for these observations. Due to a clerical error at STScI our approved Cycle15 SNAP program was barred from execution for 3 months and only 6 observations have been performed to date - reinstating this SNAP at Cycle16 priority is of paramount importance to reach meaningful statistics. WFPC2 10880 The host galaxies of QSO2s: AGN feeding and evolution at high luminosities Now that the presence of supermassive black holes in the nuclei of galaxies is a well established fact, other questions related to the AGN phenomena still have to be answered. Problems of particular interest are how the AGN gets fed, how the black hole evolves and how the evolution of the black hole is related to the evolution of the galaxy bulge. Here we propose to address some of these issues using ACS/WFC + F775W snapshot images of 73 QSO2s with redshifts in the range 0.3z0.4. These observations will be combined with similar archival data of QSO1s and ground based data of Seyfert and normal galaxies. First, we will investigate whether interactions are the most important feeding mechanism in high luminosity AGNs. This will be done in a quantitative way, comparing the asymmetry indices of QSO2 hosts with those of lower luminosity AGNs and normal galaxies. Second, we will do a detailed study of the morphology of the host galaxies of both QSO types, to determine if they are similar, or if there is an evolutionary trend from QSO2s to QSO1s. The results from this project will represent an important step in the understanding of AGN evolution, and may also introduce a substantial modification to the Unified Model. WFPC2 10877 A Snapshot Survey of the Sites of Recent, Nearby Supernovae During the past few years, robotic {or nearly robotic} searches for supernovae {SNe}, most notably our Lick Observatory Supernova Search {LOSS}, have found hundreds of SNe, many of them in quite nearby galaxies {cz 4000 km/s}. Most of the objects were discovered before maximum brightness, and have follow-up photometry and spectroscopy; they include some of the best-studied SNe to date. We propose to conduct a snapshot imaging survey of the sites of some of these nearby objects, to obtain late-time photometry that {through the shape of the light and color curves} will help reveal the origin of their lingering energy. The images will also provide high-resolution information on the local environments of SNe that are far superior to what we can procure from the ground. For example, we will obtain color-color and color-magnitude diagrams of stars in these SN sites, to determine the SN progenitor masses and constraints on the reddening. Recovery of the SNe in the new HST images will also allow us to actually pinpoint their progenitor stars in cases where pre- explosion images exist in the HST archive. This proposal is an extension of our successful Cycle 13 snapshot survey with ACS. It is complementary to our Cycle 15 archival proposal, which is a continuation of our long-standing program to use existing HST images to glean information about SN environments. FLIGHT OPERATIONS SUMMARY: Significant Spacecraft Anomalies: (The following are preliminary reports of potential non-nominal performance that will be investigated.) HSTARS: 11586 - GSAcq(1,2,1) failed to RGA Hold, search radius limit exceeded on FGS-2 GSAcq(1,2,1) scheduled at 331/10:59:34z and REAcq(1,2,1) scheduled at 331/12:33:48 failed to RGA Hold with QF2SRLEX, QF2STOPF, QSRCHEXC and QSTOP indication flags set on FGS-2. Observations affected: WFPC2 #76-79, Proposal ID #11103. 11588 - GSAcq(2,1,2) failed to RGA hold GSAcq 2,1,2 scheduled from 332/01:18:44 - 01:26:10 failed to RGA Hold at 332/01:21:43 due to QF2STOPF flag on FGS 2. Observations affected: WFPC 92-93 Proposal #10880 11590 - GSAcq (1,3,1) failed to RGA Hold due to QF1STOPF on FGS-1 At 334/02:58:55 GSAcq 1,3,1 scheduled from 02:55:18 - 03:02:42 failed to RGA Hold due to QF1STOPF flag on FGS-1. Observations affected: ACS #4, Proposal #11230 COMPLETED OPS REQUEST: (None) COMPLETED OPS NOTES: (None) ************************ SCHEDULED***** SUCCESSFUL FGS GSacq*************** 50***************** 47 FGS REacq*************** 16***************** 15 OBAD with Maneuver **** 112**************** 111 SIGNIFICANT EVENTS: (None) |
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