HST Daily Report # 3325 (part 2)
We propose to determine the composition of Io’s largest volcanic plume, Pele, with unprecedented accuracy. This will give us new constraints on the temperatures, pressures, and magma composition of this volcano, and thus an improved window into Io’s interior. We will use the proven Jupiter transit spectroscopy technique, which resulted in the discovery of S_2 gas in the Pele plume, but will use exposures that are 4 times longer than in the discovery observations. This will allow us to accurately measure plume SO_2 abundances, seen only with low S/N in the discovery observations, and possibly SO, in addition to S_2, and gives the chance to discover other, currently unknown, plume components. We will also use ACS to obtain UV and visible images of the Pele plume in reflected light prior to Jupiter transit, to constrain the dust abundance and particle size in the plume. This will allow refined estimates of plume dust/gas ratios and resurfacing rates. We will repeat the observations four times to build up S/N to even higher levels, and to look for time variability in both dust and gas abundance and chemistry.
ACS 9352
The Deceleration Test from Treasury Type Ia Supernovae at Redshifts 1.2 to 1.6
Type Ia supernovae {SNe Ia} provide the only direct evidence for an accelerating universe, an extraordinary result that needs a rigorous test. The case for cosmic acceleration rests on the observation that SNe Ia at z ~ 0.5 are ~ 0.25 mag fainter than they would be in a universe without acceleration. A powerful and straightforward way to assess the reliability of the SN Ia measurement and the conceptual framework of its interpretation is to look for cosmic deceleration at z >= 1. This would be a clear signature of a mixed dark-matter and dark-energy universe. Systematic errors in the SN Ia result attributed to grey dust or cosmic evolution of the SN Ia peak luminosity would not show this change of sign. We have demonstrated proof of this concept with a single SN Ia, SN 1997ff at z = 1.7, found and followed by HST. The results suggest an early epoch of deceleration, but this is too important a conclusion to rest on just one object. Here we propose to use HST for observations of six SNe Ia in the range 1.2 <= z <= 1.6, that will be discovered as a byproduct from proposed Treasury programs for high-latitude ACS surveys. Six objects will provide a much firmer foundation for a conclusion that touches on important questions of fundamental physics.
ACS 9454
The Nature of the UV Continuum in LINERs: A Variability Test
LINERs may be the most common AGNs, and the signposts of accretion onto the massive black holes present in most galaxies. However, the LINER spectrum is the result of UV excitation, and, in at least some LINERs, a nuclear cluster of hot stars, rather than an AGN, dominates the energetics in the UV. Thus, it is still unknown if the UV continuum, or the optical emission lines it excites, have anything to do with an AGN. The demographics and accretion physics of low-luminosity AGNs hinge on this question. We propose to search for variability in a sample of 17 LINERs with compact UV nuclei. Variability can reveal an AGN component in the UV continuum, even when its light is not dominant. We will test systematically the handful of non-definitive reports of UV variability, and potentially quantify the AGN contribution to the UV emission. Variability in all or most objects will be strong evidence that LINERs mark dormant AGNs in most galaxies. Alternatively, a general null detection of variability will suggest that, even in LINERs with additional AGN signatures, the UV continuum is stellar in origin. Contemporaneous monitoring with the VLA/VLBA of 11 objects which have radio cores {five of which we already know are radio-variable} will reveal the relations between UV and radio variations. The UV-variable objects will be targeted for future, better-sampled, monitoring.
ACS/HRC 9379
Near Ultraviolet Imaging of Seyfert Galaxies: Understanding the Starburst-AGN Connection
We propose a near-UV snapshot survey of 101 Seyfert galaxies using ACS/HRC and the filter F330W, a configuration which is optimal to detect faint star forming regions around their nuclei. These images will complement optical and near-IR images available in the HST archive, thus providing a panchromatic atlas of the inner regions of active galaxies, which we will use to study the starburst-AGN connection. The main goals of this proposal are: {1} Determine the frequency of circumnuclear starbursts in Seyferts, down to levels which cannot be observed from the ground; {2} characterize the observational {fluxes, colors, structure, sizes} and intrinsic {luminosities, masses, ages, global star-formation rate} properties of these clusters; {3} derive the luminosity functions of young star clusters around the nucleus of Seyferts and compare these results with those from normal and starburst galaxies to determine their survival rate close to the AGN; {4} address questions about the relation between AGNs and starbursts, like the possible connection between the masses and luminosities of black holes and starbursts, and the implications for the evolution of the black holes and their host galaxy bulges. By adding UV images to the existing optical and near-IR ones, this project will create an extremely valuable database for astronomers with a broad range of scientific interests, from the properties of the AGN to the properties of their host galaxies.
ACS/WFPC2 9488
Cosmic Shear – with ACS Pure Parallel Observations
The ACS, with greater sensitivity and sky coverage, will extend our ability to measure the weak gravitational lensing of galaxy images caused by the large scale distribution of dark matter. We propose to use the ACS in pure parallel {non- proprietary} mode, following the guidelines of the ACS Default Pure Parallel Program. Using the HST Medium Deep Survey WFPC2 database we have measured cosmic shear at arc-min angular scales. The MDS image parameters, in particular the galaxy orientations and axis ratios, are such that any residual corrections due to errors in the PSF or jitter are much smaller than the measured signal. This situation is in stark contrast with ground-based observations. We have also developed a statistical analysis procedure to derive unbiased estimates of cosmic shear from a large number of fields, each of which has a very small number of galaxies. We have therefore set the stage for measurements with the ACS at fainter apparent magnitudes and smaller, 10 arc-second scales corresponding to larger cosmological distances. We will adapt existing MDS WFPC2 maximum likelihood galaxy image analysis algorithms to work with the ACS. The analysis would also yield an online database similar to that in archive.stsci.edu/mds/
FGS 9348
The Distances to AM CVn stars
We propose to determine the parallaxes and proper motions of the five brightest of the seven known AM CVn systems using the HST Fine Guidance Sensors. AM CVn systems are binaries where mass is transferred from a completely hydrogen-deficient, degenerate mass donor to a white dwarf primary through a helium accretion disk. A better understanding of these systems is crucial for a number of reasons:, to study the late stages of binary evolution, to study the effect of chemical composition on the physics of accretion discs; , o to estimate their contribution to the Supernovae Ia rate and , to estimate their contribution to the gravitational radiation background. All these studies rely critically on a determination of the distances to the currently known systems. With brightnesses in the range 13<V<17 and estimated distances <400pc they are ideal targets for the HST-FGS.
NICMOS 9485
Completing A Near-Infrared Search for Very Low Mass Companions to Stars within 10 pc of the Sun
Most stars are fainter and less massive than the Sun. Nevertheless, our knowledge of very low mass {VLM} red dwarfs and their brown dwarf cousins is quite limited. Unknown are the true luminosity function {LF}, multiplicity fraction, mass function, and mass-luminosity relation for red and brown dwarfs, though they dominate the Galaxy in both numbers and total mass. The best way to constrain these relations is a search for faint companions to nearby stars. Such a search has several advantages over field surveys, including greater sensitivity to VLM objects and the availability of precise parallaxes from which luminosities and masses can be derived. We propose to complete our four-filter NICMOS snapshot search for companions to stars within 10 pc. With a 10 sigma detection limit of M_J ~ 20 at 10 pc, we can detect companions between 10 and 100 AU that are at least 9 mag fainter than the empirical end of the main sequence and at least 6.5 mag fainter than the brown dwarf Gl 229B. When completed, our search will be the largest, most sensitive, volume-limited search for VLM companions ever undertaken. Our four-filter search will permit unambiguous identification of VLM-companion candidates for follow-up observation. Together with IR speckle and deep imaging surveys, our program will firmly establish the LF for VLM companions at separations of 1-1000 AU and the multiplicity fraction of all stars within 10 pc.
NICMOS 8791
NICMOS Post-SAA calibration – CR Persistence Part 2
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.
NICMOS 9484
The NICMOS Parallel Observing Program
We propose to manage the default set of pure parallels with NICMOS. Our experience with both our GO NICMOS parallel program and the public parallel NICMOS programs in cycle 7 prepared us to make optimal use of the parallel opportunities. The NICMOS G141 grism remains the most powerful survey tool for HAlpha emission-line galaxies at cosmologically interesting redshifts. It is particularly well suited to addressing two key uncertainties regarding the global history of star formation: the peak rate of star formation in the relatively unexplored but critical 1<= z <= 2 epoch, and the amount of star formation missing from UV continuum-based estimates due to high extinction. Our proposed deep G141 exposures will increase the sample of known HAlpha emission- line objects at z ~ 1.3 by roughly an order of magnitude. We will also obtain a mix of F110W and F160W images along random sight-lines to examine the space density and morphologies of the reddest galaxies. The nature of the extremely red galaxies remains unclear and our program of imaging and grism spectroscopy provides unique information regarding both the incidence of obscured star bursts and the build up of stellar mass at intermediate redshifts. In addition to carrying out the parallel program we will populate a public database with calibrated spectra and images, and provide limited ground- based optical and near-IR data for the deepest parallel fields.
STIS 9608
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 9606
CCD Dark Monitor-Part 2
Monitor the darks for the STIS CCD.
STIS 9615
Cycle 11 MAMA Dark Monitor
This test performs the routine monitoring of the MAMA detector dark noise. This proposal will provide the primary means of checking on health of the MAMA detectors systems through frequent monitoring of the background count rate. The purpose is to look for evidence of change in dark indicative of detector problem developing.
STIS 9455
Mid-Ultraviolet Spectral Templates for Old Stellar Systems
We propose a three-year program to provide both observational and theoretical mid-ultraviolet {2300A — 3100A} spectral templates for interpreting the age and metallicity of globular clusters and elliptical galaxies from spectra of their integrated light. The mid-UV is the region most directly influenced by stellar age, and is observed directly in optical and infrared studies of high-redshift quiescent systems. The reliability of age and metallicity determinations remains questionable until non-solar metallicities and abundance ratios are considered, and stars spanning the color-magnitude diagram are included, as we propose here. With archival HST STIS spectra we have improved the list of mid-UV atomic line parameters, then calculated spectra from first principles which match observed spectra of standard stars up to one- fourth solar metallicity. We will extend both observations and calculations to stars of solar metallicity and beyond, and to those in short-lived stages hotter than the main-sequence turnoff, stars not currently well-represented in empirical libraries. The necessary line-list improvements will come from new high-resolution mid-UV spectra of nine field stars. A key application of the results of this program will be to the old systems now being discovered as `Extremely Red Objects’ at high redshifts. Reliable age-dating of these places constraints on the epoch when large structures first formed in the universe.
STIS 9417
New Clues to the Origin of the Extreme Helium Stars
The extreme helium stars {EHes} are H-poor supergiants whose origins are not yet understood despite thorough analyses of optical spectra. This proposal seeks STIS echelle spectra for 7 stars from which novel data on their chemical compositions will be obtained to pin down key abundances. First, even the EHe’s initial metallicity is uncertain; certain abundance ratios – e.g., Ca/S, Ti/S, and Fe/S – imply alterations of surface abundances among elements from Na to Ni resulting from fractionation or diffusive separation, possibly the result of winnowing of dust grains from gas. The zinc abundance measurable only from UV spectra will be a powerful clue to the true metallicity because it is known not to be removed by such winnowing. Second, elements affected by the s-process, the last of the major nucleosynthetic processes for which surface abundances are unknown for EHes, will be studied. The new abundances will be used to probe the evolutionary origins of these peculiar stars by comparisons with theoretical scenarios involving a merger of white dwarfs or a final He-shell flash in a low mass white dwarf, and with observed abundances for R Coronae Borealis stars that would seem to be close relatives of the EHes. Spectrophotometric observations of EHes obtained with GO 8603 will give accurate estimates of effective temperature and surface gravity that will be used in our abundance determinations.
STIS 9626
Slit Wheel Repeatability
Test the repeatibility of the slit wheel by taking a sequence of comparison lamp spectra with grating G230MB {2697} and the three smallest long slits {52X0.2, 52X0.1, and 52X0.05}. This is a clone of Cycle 10 Program 8913.
STIS 9706
STIS Pure Parallel Imaging Program: Cycle 10
This is the default archival pure parallel program for STIS during cycle 10.
STIS 9507
STIS/UV snapshot survey of bright AGN
We propose a UV spectroscopic snapshot survey of bright AGN, quadrupling the number of Seyferts UV spectra and adding dozens of new quasars, aimed at the following goals: beginenumerate em Finding the relationship between the intrinsic luminosity of the AGN and the maximum velocity {and width} of the outflow emanating from it, and determining the frequency of outflows in low-z AGN as a function of luminosity. em Surveying IGM absorption line systems in numerous new sight-lines. em Identifying promising targets for observations with the future highly sensitive Cosmic Origin Spectrograph. endenumerate A 35-minute snapshot with exposures in either the G140L or G230L will yield spectra with a minimum S/N > 15 per resolution element at all wavelengths for all our potential targets. This will allow us to be sensitive to absorption lines to a limiting equivalent width of 0.3 Angstrom at the 3 Sigma level. In order to facilitate rapid observational followup, we waive the data proprietary period entirely.
STIS/CCD/MA1 9459
The Response of the White Dwarf in WZ Sge to the Unexpected July 2001 Superoutburst.
The Space Telescope Imaging Spectrograph (CCD and MA1) was used to observe WZ Sge, the most extreme dwarf nova and one of the closest known cataclysmic variables, that has undergone a superoutburst in July 2001 after 22 years in quiescence. Because of the uniqueness of this event, two DD proposals were approved, one to observe the outburst itself, and another for us to observe the early decline phase. Here it is proposed to complete our fundamental study of the response of a dwarf nova system to an outburst by continuing our UV coverage of this most extreme outbursting system during its decline to quiescence. This decline is expected to take more than 3 yrs, with the most dramatic changes occurring in the first 2 years. This once-in-a-lifetime chance to obtain high quality, high time {and spectral} resolution FUV data as the decline progresses into the critical transition from the disk- dominated phase to the bare white dwarf, provides an unique opportunity to study the response of the emerging white dwarf, whose chemical abundances, rotation and temperature variation with time bear the imprint of this extraordinary gigantic accretion event.
STIS/CCD/MA2 9166
Fossil Gaseous Halos of Massive Galaxies at z~1.
The Space Telescope Imaging Spectrograph (CCD and MA2) was used to observe host galaxies of high-redshift, powerful radio sources that are likely the progenitors of present-day gE and cD galaxies, and therefore provide important laboratories in which to investigate the formation of massive galaxies in the early Universe. Many high-redshift radio galaxies exhibit giant, Ly-alpha halos. Similar nebulae without associated radio sources have recently been discovered in a galaxy overdensity at z = 3.09. The LyAlpha luminosity of these halos is comparable to the total X-ray luminosities of low–z X–ray clusters, and may reflect the hot, cooling gas reservoir from which the galaxy/cluster is forming.
STIS/MA1/CCD 9464
Exploring the Role of Acoustic Heating in Cool Dwarfs and Subgiants
Recent observations cast doubt on the importance of acoustic waves for chromospheric heating in stars. These include low upper limits to their contribution to upper layers of the solar chromosphere, and evidence for significant magnetic heating contribution even in “basal" activity stars. These findings contradict the widely accepted picture that acoustic heating accounts for a significant fraction, the “basal component”, of chromospheric heating in inactive stars. To help resolve this issue, we propose to observe two very inactive stars with significantly different properties to search for specific signatures of upward propagating acoustic waves: blue-shifts and enhanced blue wings in chromospheric lines. Solar data show that the degree of blue-shift can be used to estimate the acoustic contribution to chromospheric heating. We will compare the data to HST spectra of similar stars, and solar spectra from the SUMER instrument on SOHO. Lack of a significant acoustic signature in our targets would indicate that magnetic heating generated by a local {turbulent, non-cycling} dynamo is responsible for the basal component of chromospheric heating in inactive stars. Our targets may be in a phase analogous to the solar Maunder minimum, and the HST spectra might serve as a proxy for the solar spectrum in this state. The spectra will also be used for emission measure analysis differentially between the Sun and solar-like stars.
WFPC2 9598
Earth Flats
This proposal monitors flatfield stability. This proposal obtains sequences of Earth streak flats to construct high quality flat fields for the WFPC2 filter set. These flat fields will allow mapping of the OTA illumination pattern and will be used in conjunction with previous internal and external flats to generate new pipeline superflats. These Earth flats will complement the Earth flat data obtained during cycles 4-10.
WFPC2 9699
POMS Test Proposal: WFII backup parallel archive proposal
This is a POMS test proposal designed to simulate scientific plans.
WFPC2 9676
POMS Test Proposal: WFII parallel archive proposal
This is the generic target version of the WFPC2 Archival Pure Parallel program. The program will be used to take parallel images of random areas of the sky, following the recommendations of the 2002 Parallels Working Group.
WFPC2 9594
WFPC2 CYCLE 11 SUPPLEMENTAL DARKS pt2/3
This dark calibration program obtains 3 dark frames every day to provide data for monitoring and characterizing the evolution of hot pixels
Significant Spacecraft Anomalies: (The following are preliminary reports of potential non-nominal performance that will be investigated.)
HSTAR 8967: FHST U2,3FM updates scheduled @ 083/01:08:30Z and 083/01:11:15Z failed due to Error Box result failed message "2Failed" in mnemonics QEBSTFG(0,1,2). Following GS Acquisition (3,2,3) passed. Following FAD scheduled @ 083/01:22:16Z read errors equaling 54.140, -1.758, and -0.487 arcsec. Under investigation.The guide star acquisition for this observation was non-nominal, further analysis will determine if a repeat observation is required.
HSTAR 8968: FHST U2,3RD update scheduled @ 083/03:02:14Z failed due to Error Box result failed message "2 Failed" in mnemonics QEBSTFG(0,1) and "2&3 Failed" in mnemonic QEBSTFG2. Following U1,3FM updates passed along with GS Acquisition (3,2,3). Following FAD scheduled @ 083/04:25:38Z read errors equaling 5.143, -4.348, and 2.622 arcsec. Under investigation.The guide star acquisition for this observation was non-nominal, further analysis will determine if a repeat observation is required.
HSTAR 8969: GS Acquisition (2,1,2) @ 083/06:05:22Z failed to RGA only Mode due to SRLE on FGS 2 during LOS. Prior FHST FM update U2,3FM @ 083/06:32:49Z and subsequent updates all passed. Following GS Acquisition (3,1,3) @ 083/07:37:37Z passed. Four Status Buffer messages (STIS 710) were received due to GS Acquisition failure. Not enough time between the two acquisition to scheduled real-time FHST map. Under investigation.The guide star acquisition for this observation was non-nominal, further analysis will determine if a repeat observation is required.
COMPLETED OPS REQs: None
OPS NOTES EXECUTED: None
SCHEDULED SUCCESSFUL FAILURE TIMES FGS GSacq 26 25 083/0650z FGS REacq 20 20 FHST Update 58 55 083/0108z, 083/0111z, 083/0302z LOSS of LOCK
SIGNIFICANT EVENTS:
Successfully completed Command Communication Controller (CCC) test 080/13:20Z-14:30Z. Testing was conducted out of the SMOR using CCCs located in the SMOR and GDOC. The Long Duration System test was started with machines located in the SMOR, MOR, and Building 23 loaded with the following clients: HSTnet = 646, Backbone = 631, and Core = 120.
CCS 4.0.2 "C" String Command Testing followed by additional HITT Testing scheduled 083/12:00Z – 21:00Z with GDOC SOC, HITT, and CCS using CCS "C" String with Release 4.0.2 and PRD S07102. The purpose of this testing is to very the CCS Ground System can effectively command in various modes and scenarios used on-orbit using CCS Release 4.0.2 on the "C" String.
