NASA Hubble Space Telescope Daily Report #5116
HUBBLE SPACE TELESCOPE DAILY REPORT #5116
Continuing to Collect World Class Science
PERIOD COVERED: 5am June 11 – 5am June 14, 2010 (DOY 162/09:00z-165/09:00z)
FLIGHT OPERATIONS SUMMARY:
Significant Spacecraft Anomalies: (The following are preliminary reports of potential non-nominal performance that will be investigated.)
HSTARS:
12299 – GSAcq(1,2,1) scheduled at 163/17:35:50z, the REAcqs(1,2,1) scheduled at 163/18:55:04z, at 163/20:30:44z at 163/22:06:24z and at 163/23:42:04z all acquired fine lock backup on FGS 2 due to scan step limit exceeded on FGS 1.
Observations possibly affected: COS 99 – 178, Proposal ID#11686.
12300 – REAcq(2,1,1) scheduled at 164/02:52:12z took two attempts to achieve CT-DV.
Observations possibly affected: COS 179 Proposal ID#11698, WFC3 170-171 Proposal ID#11905, ACS 88 Proposal ID#11995.
12301 – REAcq(1,2,1) scheduled at 165/02:46:24 failed.
Observations affected: WFC3 3 – 5 Proposal ID#11588
COMPLETED OPS REQUEST: (None)
COMPLETED OPS NOTES: (None)
SCHEDULED SUCCESSFUL
FGS GSAcq 21 21
FGS REAcq 32 31
OBAD with Maneuver 12 12
SIGNIFICANT EVENTS: (None)
OBSERVATIONS SCHEDULED:
COS/FUV 11997
FUV Internal/External Wavelength Scale Monitor
This program monitors the offsets between the wavelength scale set by the internal wavecal versus that defined by absorption lines in external targets. This is accomplished by observing two external targets in the SMC: SK191 with G130M and G160M and Cl* NGC 330 ROB B37 with G140L (SK191 is too bright to be observed with G140L). The cenwaves observed in this program are a subset of the ones used during Cycle 17. Observing all cenwaves would require a considerably larger number of orbits. Constraints on scheduling of each target are placed so that each target is observed once every ~2-3 months. Observing the two targets every month would also require a considerably larger number of orbits.
ACS/WFC 11995
CCD Daily Monitor (Part 2)
This program comprises basic tests for measuring the read noise and dark current of the ACS WFC and for tracking the growth of hot pixels. The recorded frames are used to create bias and dark reference images for science data reduction and calibration. This program will be executed four days per week (Mon, Wed, Fri, Sun) for the duration of Cycle 17. To facilitate scheduling, this program is split into three proposals. This proposal covers 320 orbits (20 weeks) from 1 February 2010 to 20 June 2010.
WFC3/IR/S/C 11929
IR Dark Current Monitor
Analyses of ground test data showed that dark current signals are more reliably removed from science data using darks taken with the same exposure sequences as the science data, than with a single dark current image scaled by desired exposure time. Therefore, dark current images must be collected using all sample sequences that will be used in science observations. These observations will be used to monitor changes in the dark current of the WFC3-IR channel on a day-to-day basis, and to build calibration dark current ramps for each of the sample sequences to be used by Gos in Cycle 17. For each sample sequence/array size combination, a median ramp will be created and delivered to the calibration database system (CDBS).
WFC3/UVIS 11912
UVIS Internal Flats
This proposal will be used to assess the stability of the flat field structure for the UVIS detector throughout the 15 months of Cycle 17. The data will be used to generate on-orbit updates for the delta-flat field reference files used in the WFC3 calibration pipeline, if significant changes in the flat structure are seen.
WFC3/UVIS 11908
Cycle 17: UVIS Bowtie Monitor
Ground testing revealed an intermittent hysteresis type effect in the UVIS detector (both CCDs) at the level of ~1%, lasting hours to days. Initially found via an unexpected bowtie-shaped feature in flatfield ratios, subsequent lab tests on similar e2v devices have since shown that it is also present as simply an overall offset across the entire CCD, i.e., a QE offset without any discernable pattern. These lab tests have further revealed that overexposing the detector to count levels several times full well fills the traps and effectively neutralizes the bowtie. Each visit in this proposal acquires a set of three 3×3 binned internal flatfields: the first unsaturated image will be used to detect any bowtie, the second, highly exposed image will neutralize the bowtie if it is present, and the final image will allow for verification that the bowtie is gone.
WFC3/UVIS 11905
WFC3 UVIS CCD Daily Monitor
The behavior of the WFC3 UVIS CCD will be monitored daily with a set of full-frame, four-amp bias and dark frames. A smaller set of 2Kx4K subarray biases are acquired at less frequent intervals throughout the cycle to support subarray science observations. The internals from this proposal, along with those from the anneal procedure (Proposal 11909), will be used to generate the necessary superbias and superdark reference files for the calibration pipeline (CDBS).
STIS/CC 11847
CCD Bias Monitor-Part 2
Monitor the bias in the 1×1, 1×2, 2×1, and 2×2 bin settings at gain=1, and 1×1 at gain = 4, to build up high-S/N superbiases and track the evolution of hot columns.
STIS/CC 11845
CCD Dark Monitor Part 2
Monitor the darks for the STIS CCD.
NIC1/NIC2 11818
NICMOS Confirmation of an Extrasolar pPanet Candidate Directly Detected with ACS
With ACS/HRC coronagraphy, we have achieved the direct detection of a planet candidate in F606W and F814W around a bright nearby star with a debris belt. The planet candidate lies 18 astronomical units interior to the dust belt and we detect counterclockwise orbital motion in observations separated by 1.75 years. The candidate has mass no greater than three Jupiter masses based on an analysis of its luminosity and the dynamical argument that a significantly more massive object would disrupt the dust belt. Using recent model predictions for 100-300 Myr old planetary atmospheres, the planet candidate has a temperature of ~400 K and a mass 1.6 – 3.4 M_J. Variability at optical wavelengths suggests additional sources of luminosity such as H-alpha emission or the episodic accretion of cometary material. A key surprise is that the planet candidate is NOT detected in Keck adaptive optics observations at 1.6 microns. Two model atmospheres predict a flux a few times greater than our detection limit, though the model predictions disagree with each other by a factor of five due to theoretical uncertainty in the strength of CH4 vibrational bands. These models predict the strongest emission centered on the F110W passband of NICMOS such that the F814W – F110W color will be red. Here we propose follow-up NICMOS observations to verify that the emission observed in F814W is due to the emergent flux from passive cooling of the planet, as opposed to other explanations, such as reflected light from a Saturn analog with a circumplanetary debris disk that would produce a bluer F814W – F110W color. Additional deep images in and and out of the 1.14 micron water trough using NIC1 narrowband filters will test whether or not the emission is produced from the passive cooling of a young massive planet.
COS/FUV/NUV 11733
WPVS 007: the little AGN that could
Outflows are important components of AGN, potentially removing angular momentum, enriching the intergalactic medium, and potentially playing a key role in the evolution of galaxies. Yet their astrophysics is poorly understood. We propose an FUV observation of the Seyfert-luminosity AGN WPVS 007 (M_V=-19.7, z=0.02882) using COS, coordinated with a short Chandra observation. Observed to have a miniBAL with maximum velocity v_max~1000 km/s in an 1996 HST observation, it was discovered to have developed an additional BAL flow by the time of the FUSE observation in 2003. The BAL flow has maximum velocity of at least 6, 000 km/s, and the unambiguous presence of PV indicates that it is very optically thick. In addition, it was found to have normal X-ray flux during the ROSAT All Sky Survey, but in subsequent observations from 1993 to 2003 it was observed to be X-ray weak, suggesting that the X-rays were absorbed by the emerging BAL.
Our proposed observations will contribute to our understanding of outflows in three key areas. First, an observed relationship between v_max and luminosity that is plausibly related to the acceleration mechanism is violated in WPVS 007; thus WPVS 007 presents a challenge to outflow models. Second, the observed evolution of the BAL flow may be related to the small black hole mass and correspondingly compact emission and absorption regions; thus, WPVS 007 offers the rare opportunity to observe evolution of the outflow on human time scales. Finally, while WPVS 007 has been observed to be X-ray weak since 1993, a recent long Swift observation revealed the first detection of hard X-ray emission. The proposed observations will reveal whether this emergence of hard X-rays is accompanied by a decrease in the UV absorption, and thus test the relationship between X-ray and UV absorbers in BALQSOs.
WFC3/UVIS 11730
Continued Proper Motions of the Magellanic Clouds: Orbits, Internal Kinematics, and Distance
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. The results had a number of unexpected implications for the Milky Way-LMC-SMC system and received considerable attention in the literature and in the press. The implied three-dimensional velocities are larger than previously believed and close to the escape velocity in a standard 10^12 solar mass Milky Way dark halo. Our orbit calculations suggest the Clouds may not be bound to the Milky Way or may just be on their first passage, both of which are unexpected in view of traditional interpretations of the Magellanic Stream. Alternatively, the Milky Way dark halo may be a factor 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 was 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 requested an additional epoch data in Cycle 16 which is being executed with WFPC2/PC due to the failure of ACS. A detailed analysis of one LMC field shows that the field proper motion using all three epochs of data is consistent within 1-sigma with the two- epoch data, thus verifying that there are no major systematic effects in our previous measurements. The random errors, however, are only smaller by a factor of 1.4 because of the relatively large errors in the WFPC2 data. A prediction for a fourth epoch with measurement errors similar to epochs 1 and 2 shows that the uncertainties will improve by a factor of 3. This will allow us to 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 to determine a distance to the LMC using rotational parallax. Continuation of this highly successful program is therefore likely to provide important additional insights. Execution in SNAPshot mode guarantees maximally efficient use of HST resources.
COS/NUV/FUV 11720
Detailed Analysis of Carbon Atmosphere White Dwarfs
We propose to obtain UV spectra for the newly discovered white dwarf stars with a carbon- dominated atmosphere. Model calculations show that these stars emit most of their light in the UV part of the electromagnetic spectrum and that an accurate determination of the flux in this region is crucial for an accurate determination of the atmospheric parameters. It will also provide a unique opportunity to test the atomic data and broadening theory in stellar conditions never met before. This will play a primordial role in our path to understand the origin of these objects as well to obtain a better understanding of the evolution of stars in general. The principal objective we hope to achieve with these observations are 1) obtain accurate surface gravity/mass for these stars, 2) constrain/determine the abundance of other elements (O, He, Mg, Ne etc.), especially oxygen, 3) verify the accuracy of the various theoretical atomic data used in the model calculations, 4) understand the origin and evolution of carbon atmosphere white dwarfs, in particular whether progenitor stars as massive as 10.5 solar masses can produce white dwarfs, rather than supernovae. We propose to observe 5 objects chosen carefully to cover the range of observed properties among carbon atmosphere white dwarfs (effective temperature, surface gravity, abundance of hydrogen/helium and magnetic field).
WFC3/IR 11719
A Calibration Database for Stellar Models of Asymptotic Giant Branch Stars
Studies of galaxy formation and evolution rely increasingly on the interpretation and modeling of near-infrared observations. At these wavelengths, the brightest stars are intermediate mass asymptotic giant branch (AGB) stars. These stars can contribute nearly 50% of the integrated luminosity at near infrared and even optical wavelengths, particularly for the younger stellar populations characteristic of high-redshift galaxies (z>1). AGB stars are also significant sources of dust and heavy elements. Accurate modeling of AGB stars is therefore of the utmost importance.
The primary limitation facing current models is the lack of useful calibration data. Current models are tuned to match the properties of the AGB population in the Magellanic Clouds, and thus have only been calibrated in a very narrow range of sub-solar metallicities. Preliminary observations already suggest that the models are overestimating AGB lifetimes by factors of 2-3 at lower metallicities. At higher (solar) metallicities, there are no appropriate observations for calibrating the models.
We propose a WFC3/IR SNAP survey of nearby galaxies to create a large database of AGB populations spanning the full range of metallicities and star formation histories. Because of their intrinsically red colors and dusty circumstellar envelopes, tracking the numbers and bolometric fluxes of AGB stars requires the NIR observations we propose here. The resulting observations of nearby galaxies with deep ACS imaging offer the opportunity to obtain large (100-1000’s) complete samples of AGB stars at a single distance, in systems with well-constrained star formation histories and metallicities.
WFC3/UVIS/IR 11702
Search for Very High-z Galaxies with WFC3 Pure Parallel
WFC3 will provide an unprecedented probe to the early universe beyond the current redshift frontier. Here we propose a pure parallel program using this new instrument to search for Lyman-break galaxies at 6.5< z<8.8 and to probe the epoch of reionization, a hallmark event in the history of the early universe. We request 200 orbits, spreading over 30 ~ 50 high Galactic latitude visits (|b|>20deg) that last for 4 orbits and longer, resulting a total survey area of about 140~230 square arcminute. Based on our understanding of the new HST parallel observation scheduling process, we believe that the total number of long-duration pure parallel visits in Cycle 17 should be sufficient to accommodate our program. We waive all proprietary rights to our data, and will also make the enhanced data products public in a timely manner.
(1) We will use both the UVIS and the IR channels, and do not need to seek optical data from elsewhere.
(2) Our program will likely triple the size of the probable candidate samples at z~7 and z~8, and will complement other targeted programs aiming at the similar redshift range.
(3) Being a pure parallel program, our survey will only make very limited demand on the scarce HST resources. More importantly, as the pure parallel pointings will be at random sight-lines, our program will be least affected by the bias due to the large scale structure (“cosmic variance”).
(4) We aim at the most luminous LBG population, and will address the bright-end of the luminosity function at z~8 and z~7. We will constrain the value of L* in particular, which is critical for understanding the star formation process and the stellar mass assembly history in the first few hundred million years of the universe.
(5) The candidates from our survey, most of which will be the brightest ones that any surveys would be able to find, will have the best chance to be spectroscopically confirmed at the current 8–10m telescopes.
(6) We will also find a large number of extremely red, old galaxies at intermediate redshifts, and the fine spatial resolution offered by the WFC3 will enable us constrain their formation history based on the study of their morphology, and hence shed light on their connection to the very early galaxies in the universe.
COS/NUV/FUV 11698
The Structure and Dynamics of Virgo’s Multi-Phase Intracluster Medium
The dynamical flows of the intracluster medium (ICM) are largely unknown. We propose to map the spatial and kinematic distribution of the warm ICM of the nearby Virgo cluster using the Cosmic Origins Spectrograph. 15 sightlines at a range of impact parameters within the virial radius of the cluster (0.2 – 1.7 Mpc) will be probed for Lyman-alpha absorption and the data compared to blind HI, dust and x-ray surveys to create a multi-phase map of the cluster’s ICM. Absorption line sightlines are commonly 40-100 kpc from a galaxy, allowing the flow of baryons between galaxies and the ICM to be assessed. The velocity distribution of the absorbers will be directly compared to simulations and used to constrain the turbulent motions of the ICM. This proposal will result in the first map of a cluster’s warm ICM and provide important tests for our theoretical understanding of cluster formation and the treatment of gas cooling in cosmological simulations.
WFC3/IR 11694
Mapping the Lnteraction Between High-Redshift Galaxies and the Lntergalactic Environment
With the commissioning of the high-throughput large-area camera WFC3/IR, it is possible for the first time to undertake an efficient survey of the rest-frame optical morphologies of galaxies at the peak epoch of star formation in the universe. We therefore propose deep WFC3/IR imaging of over 320 spectroscopically confirmed galaxies between redshift 1.6 < z < 3.4 in well-studied fields which lie along the line of sight to bright background QSOs. The spectra of these bright QSOs probe the IGM in the vicinity of each of the foreground galaxies along the line of sight, providing detailed information on the physical state of the gas at large galactocentric radii. In combination with our densely sampled UV/IR spectroscopy, stellar population models, and kinematic data in these fields, WFC3/IR imaging data will permit us to construct a comprehensive picture of the structure, dynamics, and star formation properties of a large population of galaxies in the early universe and their effect upon their cosmological environment. COS/FUV 11686 The Cosmological Impact of AGN Outflows: Measuring Absolute Abundances and Kinetic Luminosities AGN outflows are increasingly invoked as a major contributor to the formation and evolution of supermassive black holes, their host galaxies, the surrounding IGM, and cluster cooling flows. Our HST/COS proposal will determine reliable absolute chemical abundances in six AGN outflows, which influences several of the processes mentioned above. To date there is only one such determination, done by our team on Mrk 279 using 16 HST/STIS orbits and 100 ksec of FUSE time. The advent of COS and its high sensitivity allows us to choose among fainter objects at redshifts high enough to preclude the need for FUSE. This will allow us to determine the absolute abundances for six AGN (all fainter than Mrk 279) using only 40 HST COS orbits. This will put abundances studies in AGN on a firm footing, an elusive goal for the past four decades. In addition, prior FUSE observations of four of these targets indicate that it is probable that the COS observations will detect troughs from excited levels of C III. These will allow us to measure the distances of the outflows and thereby determine their kinetic luminosity, a major goal in AGN feedback research. 11686( 7) – 25-Sep-2009 13:44:14 – [ 2] We will use our state of the art column density extraction methods and velocity-dependent photoionization models to determine the abundances and kinetic luminosity. Previous AGN outflow projects suffered from the constraints of deciding what science we could do using ONE of the handful of bright targets that were observable. With COS we can choose the best sample for our experiment. As an added bonus, most of the spectral range of our targets has not been observed previously, greatly increasing the discovery phase space. WFC3/ACS/IR 11677 Is 47 Tuc Young? Measuring its White Dwarf Cooling Age and Completing a Hubble Legacy With this proposal we will firmly establish the age of 47 Tuc from its cooling white dwarfs. 47 Tuc is the nearest and least reddened of the metal-rich disk globular clusters. It is also the template used for studying the giant branches of nearby resolved galaxies. In addition, the age sensitive magnitude spread between the main sequence turnoff and horizontal branch is identical for 47 Tuc, two bulge globular clusters and the bulge field population. A precise relative age constraint for 47 Tuc, compared to the halo clusters M4 and NGC 6397, both of which we recently dated via white dwarf cooling, would therefore constrain when the bulge formed relative to the old halo globular clusters. Of particular interest is that with the higher quality ACS data on NGC 6397, we are now capable with the technique of white dwarf cooling of determining ages to an accuracy of +/-0.4 Gyrs at the 95% confidence level. Ages derived from the cluster turnoff are not currently capable of reaching this precision. The important role that 47 Tuc plays in galaxy formation studies, and as the metal-rich template for the globular clusters, makes the case for a white dwarf cooling age for this metal-rich cluster compelling. Several recent analyses have suggested that 47 Tuc is more than 2 Gyrs younger than the Galactic halo. Others have suggested an age similar to that of the most metal poor globular clusters. The current situation is clearly uncertain and obviously a new approach to age dating this important cluster is required. With the observations of 47 Tuc, this project will complete a legacy for HST. It will be the third globular cluster observed for white dwarf cooling; the three covering almost the full metallicity range of the cluster system. Unless JWST has its proposed bluer filters (700 and 900 nm) this science will not be possible perhaps for decades until a large optical telescope is again in space. Ages for globular clusters from the main sequence turnoff are less precise than those from white dwarf cooling making the science with the current proposal truly urgent. ACS/WFC3 11669 The Origins of Short Gamma-Ray Bursts During the past decade extraordinary progress has been made in determining the origin of long- duration gamma-ray bursts. It has been conclusively shown that these objects derive from the deaths of massive stars. Nonetheless, the origin of their observational cousins, short-duration gamma-ray bursts (SGRBs) remains a mystery. While SGRBs are widely thought to result from the inspiral of compact binaries, this is a conjecture. SGRBs have been found in elliptical galaxies, Abell Clusters, star-forming dwarfs and even an edge-on spiral. Whether they primarily result from an old population, a young population, or rapid evolution of binaries in globular clusters remains open. Here we propose to employ two related sets of observations which may dramatically advance our understanding of short bursts. The first is a variant of a technique that we pioneered and used to great effect in elucidating the origins of long-duration bursts. We will examine a statistical sample of hosts and measure the degree to which SGRB locations trace the red or blue light of their hosts, and thus old or young stellar populations. This will allow us to study the demographics of the SGRB population in a manner largely free of the distance dependent selection effects which have so far bedeviled this field. In the second line of attack we will use two targets of opportunity to obtain extremely precise positions of up to two nearby bursts — one on a star-forming galaxy and the other on a elliptical. Observation of the star-formation galaxy could link at least some bursts directly to a young population; however, a discovery in later images of a globular cluster at the site of the explosion in an elliptical would provide revolutionary evidence that SGRBs are formed from compact binaries. WFC3/UV 11635 In Search of SNIb/Ic Wolf-Rayet Progenitors and Comparison with Red Supergiants (SNII Progenitors) in the Giant ScI Spiral M101 We propose to test two of the clearest predictions of the theory of evolution of massive-star evolution: 1) The formation of Wolf-Rayet stars depends strongly on these stars’ metallicity (Z), with relatively fewer WR stars forming at lower Z, and 2) Wolf-Rayet stars die as Type Ib or Ic supernovae. To carry out these tests we propose a deep, narrowband imaging survey of the massive star populations in the ScI spiral galaxy M101. Just as important, we will test the hypothesis that Superclusters like 30 Doradus are always richly populated with WR stars, and by implication that these complexes are responsible for the spectral signatures of starburst galaxies. Our previous HST survey of the HII regions in the ScIII galaxy NGC 2403 suggested that the distribution of WR stars and RSG is a sensitive diagnostic of the recent star-forming history of these large complexes: young cores of O and WR stars are surrounded by older halos containing RSG. Theory predicts that this must change with metallicity; relatively fewer WR stars form at lower Z. A key goal of our proposal is to directly test this paradigm in a single galaxy, M101 being the ideal target. The abundance gradient across M101 (a factor of 20) suggests that relatively many more WR will be found in the inner parts of this galaxy than in the outer “suburbs”. Second, we note that WR stars are predicted to end their lives as core-collapse or pair-instability supernovae. The WR population in M101 may be abundant enough for one to erupt as a Type Ib or Ic supernova within a generation. The clear a priori identification of a WR progenitor would be a major legacy of HST. Third, we will also determine if “superclusters”, heavily populated by WR stars, are common in M101. It is widely claimed that such Superclusters produce the integrated spectral signatures of Starburst galaxies. We will be able to directly measure the numbers and emission-line luminosities of thousands of Wolf Rayet stars located in hundreds of M101 Superclusters, and correlate those numbers against the Supercluster sizes and luminosities. It is likely (but far from certain) that Supercluster sizes and emission-line luminosities are driven by their Wolf-Rayet star content. Our sample will be the largest and best-ever Supercluster/Wolf Rayet sample, an excellent local proxy for characterizing starburst galaxies’ Superclusters. WFC3/ACS/UVIS 11613 GHOSTS: Stellar Outskirts of Massive Spiral Galaxies We propose to continue our highly successful GHOSTS HST survey of the resolved stellar populations of nearby, massive disk galaxies using SNAPs. These observations provide star counts and color-magnitude diagrams 2-3 magnitudes below the tip of the Red Giant Branch of the outer disk and halo of each galaxy. We will measure the metallicity distribution functions and stellar density profiles from star counts down to very low average surface brightnesses, equivalent to ~32 V-mag per square arcsec. This proposal will substantially improve our unique sampling of galaxy outskirts. Our targets cover a range in galaxy mass, luminosity, inclination, and morphology. As a function of these galaxy properties, this survey provides: – the most extensive, systematic measurement of radial light profiles and axial ratios of the diffuse stellar halos and outer disks of spiral galaxies; – a comprehensive analysis of halo metallicity distributions as function of galaxy type and position within the galaxy; – an unprecedented study of the stellar metallicity and age distribution in the outer disk regions where the disk truncations occur; – the first comparative study of globular clusters and their field stellar populations. We will use these fossil records of the galaxy assembly process to test halo formation models within the hierarchical galaxy formation scheme. WFC3/ACS/UVIS 11603 A Comprehensive Study of Dust Formation in Type II Supernovae with HST, Spitzer, and Gemini The recent discovery of three extremely bright Type II SNe, (2007it, 2007oc, 2007od) gives us a unique opportunity to combine observations with HST, Spitzer, and Gemini to study the little understood dust formation process in Type II Sne. Priority 1 Spitzer Cycle 5 and band 1 Gemini 2008A time has already been approved for this project. Since late-time Type II Sne are faint and tend to be in crowded fields, we need the high sensitivity and high spatial resolution of ACS and NICMOS/NIC2 for these observations. This project is motivated by the recent detection of large amounts of dust in high redshift galaxies. The dust in these high-z galaxies must come from young, massive stars so Type II Sne could be potential sources. The mechanism and the efficiency of dust condensation in Type II SN ejecta are not well understood, largely due to the lack of observational data. We plan to produce a unique dataset, combining spectroscopy and imaging in the visible, near- and mid-IR covering the key phase, 400-700 days after maximum when dust is known to form in the SN ejecta. Therefore, we are proposing for coordinated HST/NOAO observations (HST ACS, NICMOS/NIC2 & Gemini/GMOS and TReCS) which will be combined with our Spitzer Cycle 5 data to study these new bright Sne. The results of this program will place strong constraints on the formation of dust seen in young high redshift (z>5) galaxies.
WFC3/UVIS 11588
Galaxy-Scale Strong Lenses from the CFHTLS Survey
We aim to investigate the origin and evolution of early-type galaxies using gravitational lensing, modeling the mass profiles of objects over a wide range of redshifts. The low redshift (z = 0.2) sample is already in place following the successful HST SLACS survey; we now propose to build up and analyze a sample of comparable size (~50 systems) at high redshift (0.4 < z < 0.9) using HST WFC3 Snapshot observations of lens systems identified by the SL2S collaboration in the CFHT legacy survey. STIS/CCD/MA2 11568 A SNAPSHOT Survey of the Local Interstellar Medium: New NUV Observations of Stars with Archived FUV Observations We propose to obtain high-resolution STIS E230H SNAP observations of MgII and FeII interstellar absorption lines toward stars within 100 parsecs that already have moderate or high-resolution far-UV (FUV), 900-1700 A, observations available in the MAST Archive. Fundamental properties, such as temperature, turbulence, ionization, abundances, and depletions of gas in the local interstellar medium (LISM) can be measured by coupling such observations. Due to the wide spectral range of STIS, observations to study nearby stars also contain important data about the LISM embedded within their spectra. However, unlocking this information from the intrinsically broad and often saturated FUV absorption lines of low-mass ions, (DI, CII, NI, OI), requires first understanding the kinematic structure of the gas along the line of sight. This can be achieved with high resolution spectra of high-mass ions, (FeII, MgII), which have narrow absorption lines, and can resolve each individual velocity component (interstellar cloud). By obtaining short (~10 minute) E230H observations of FeII and MgII, for stars that already have moderate or high- resolution FUV spectra, we can increase the sample of LISM measurements, and thereby expand our knowledge of the physical properties of the gas in our galactic neighborhood. STIS is the only instrument capable of obtaining the required high resolution data now or in the foreseeable future. STIS/CCD 11567 Boron Abundances in Rapidly Rotating Early-B Stars Models of rotation in early-B stars predict that rotationally driven mixing should deplete surface boron abundances during the main-sequence lifetime of many stars. However, recent work has shown that many boron depleted stars are intrinsically slow rotators for which models predict no depletion should have occurred, while observations of nitrogen in some more rapidly rotating stars show less mixing than the models predict. Boron can provide unique information on the earliest stages of mixing in B stars, but previous surveys have been biased towards narrow- lined stars because of the difficulty in measuring boron abundances in rapidly rotating stars. The two targets observed as part of our Cycle 13 SNAP program 10175, just before STIS failed, demonstrate that it is possible to make useful boron abundance measurements for early-B stars with Vsin(i) above 100 km/s. We propose to extend that survey to a large enough sample of stars to allow statistically significant tests of models of rotational mixing in early-B stars. WFC3/UVIS 11565 A Search for Astrometric Companions to Very Low-Mass, Population II Stars We propose to carry out a Snapshot search for astrometric companions in a subsample of very low-mass, halo subdwarfs identified within 120 parsecs of the Sun. These ultra-cool M subdwarfs are local representatives of the lowest-mass H burning objects from the Galactic Population II. The expected 3-4 astrometric doubles that will be discovered will be invaluable in that they will be the first systems from which gravitational masses of metal-poor stars at the bottom of the main sequence can be directly measured. WFC3/UV 11556 Investigations of the Pluto System We propose a set of high SNR observations of the Pluto system that will provide improved lightcurves, orbits, and photometric properties of Nix and Hydra. The key photometric result for Nix and Hydra will be a vastly improved lightcurve shape and rotation period to test if the objects are in synchronous rotation or not. A second goal of this program will be to retrieve a new epoch of albedo map for the surface of Pluto. These observations will also improve masses and in some case densities for the bodies in the Pluto system. NIC 11495 The first direct detection of an extrasolar planetary stratosphere? We request NICMOS grism spectroscopy to observe the transit of WASP-3b. This newly discovered planet is the hottest nearby planet discovered so far. The atmosphere is predicted to be so hot that TiO and VO remain in the gas phase, creating a hot, strongly absorbing stratosphere. This molecular absorption will cause a 6% enhancement in the transit depth at 0.8 microns, compared to that at 1.3 microns. NICMOS/G096 and NICMOS/G141 observations will therefore provide a straightforward test of the hot stratosphere hypothesis. The HST observations will provide a precisely determined radius measurement. This is required to drive advances in theories of planetary formation, evolution, and atmospheric physics and chemistry. The atmospheric TiO and VO absorption is predicted to cause an anomalously high IR brightness temperature for the planet. We need HST’s direct test of the hot stratosphere hypothesis promptly to enable appropriate cold-Spitzer observations to be planned and interpreted. Spitzer is likely to exhaust its cryogens before these observations could be scheduled via the cycle 17 GO process.
