NASA Hubble Space Telescope Daily Report #3957
HUBBLE SPACE TELESCOPE – Continuing to collect World Class Science
DAILY REPORT # 3957
PERIOD COVERED: UT September 30-02, 2005 (DOY 273-275)
OBSERVATIONS SCHEDULED
NIC1/NIC2/NIC3 8793
NICMOS Post-SAA calibration – CR Persistence Part 4
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.
ACS/HRC 10752
Cycle 14 Focus Monitor
The focus of HST is measured primarily with ACS/HRC over full CVZ orbits to obtain accurate mean focus values via a well sampled breathing curve. Coma and astigmatism are also determined from the same data in order to further understand orbital effects on image quality and optical alignments. To monitor the stability of ACS to WFPC2 relative focii, we’ve carried over from previous focus monitor programs parallel observations taken with the two cameras at suitable orientations of previously observed targets, and interspersed them with the HRC CVZ visits.
ACS/HRC/WFC 10729
ACS CCDs daily monitor
This program consists of a set of basic tests to monitor, the read noise, the development of hot pixels and test for any source of noise in ACS CCD detectors. The files, biases and dark will be used to create reference files for science calibration. This programme will be for the entire lifetime of ACS. Changes from cycle 13:- The default gain for WFC is 2 e-/DN. As before bias frames will be collected for both gain 1 and gain 2. Dark frames are acquired using the default gain {2}. This program cover the period Oct, 2 2005- May, 29-2006. The second half of the program has a different proposal number: 10758.
S/C/NIC1 10724
NICMOS Focus Monitoring
The purpose of this proposal is to determine the best focus for all three NICMOS detectors. The program will be executed every ~6 weeks. Each execution will concern a single detector, except two occasions which will include NIC3. In total NIC1 and NIC2 will be monitored 4 times each during the current cycle, while NIC3 will only be monitored twice. The program starts with a focus sweep using only the NIC1 camera {visit 11}. The following observation is with the NIC2 camera {visit 12} after about 45 days. This pattern is repeated throughout the period except for Jan 1-8 and Jul 1-8 where also the NIC3 camera is used. In total this will result in 10 orbits. Notice that VISIT #1 #2 refers to visits for #1 sequential visit number for a given camera #2 camera in question visit 32 is therefore the third visit for camera 2. Some tweaking of dates and sources are necessary to ensure visibility under 2-gyro mode. These are the dates and targets for Cycel14: Visit 11: Oct 01-08 NIC1 NGC1850 Visit 12: Nov 15-22 NIC2 NGC3603 Visit 21: Jan 01-15 NIC1 NGC3603 Visit 13: Jan 01-15 NIC3 NGC3603 Visit 22: Feb 15-22 NIC2 NGC3603 Visit 31: Apr 01-15 NIC1 NGC1850 Visit 32: May 22-31 NIC2 NGC3603 Visit 41: Jun 15-22 NIC1 NGC1850 Visit 23: Jun 15-22 NIC3 NGC1850 Visit 42: Aug 07-22 NIC2 NGC3603
ACS/HRS 10722
SBC geometric distortions and ACS UV L-flats
The primary goal of this calibration program is to improve the accuracy of the geometric distortion solution for the ACS/SBC imaging modes and to calculate the geometric solution for PR130L for the first time. The secondary goals are to generate an L-flat for PR130L and to provide independent checks for the L-flat and quantum efficiencies of the SBC
ACS/WFC 10615
Timing Studies of the X-ray Binary Populations in Globular Clusters
Close binaries are fundamental to the dynamical stability and evolution of globular clusters, but large populations have been extremely difficult to identify. Chandra X-ray images provide a revolutionary resource, revealing a few to dozens of low-luminosity X-ray sources in every cluster deeply examined; our own Chandra programs uniformly study these ubiquitous X-ray sources {close binaries and their progeny} in a dozen clusters. We have obtained multicolor, single-epoch, ACS images, from which to obtain initial optical counterparts, especially CVs {the dominant population in most clusters}, BY Dra’s, and qLMXBs. As HST capability for follow-on, confirming, spectra of our multicolor-selected counterparts is now severely curtailed, we propose an ACS time-series imaging program that will yield equivalent follow-on information for 5 of our clusters. The proposed ACS time-series data with 6 min resolution and 8 hr time-span, will: provide variability information to secure our suggested multicolor identifications; allow secure classifications of the various X-ray subpopulations {e.g., CVs vs. BY Dra’s}; yield quality lightcurves, whose shape will help test the notion that magnetic CVs are more common in globular clusters than the field; and, provide interesting contraints on the period distributions of cluster X-ray binaries.
NIC2 10603
Multiwavelength Imaging of Edge-on Protoplanetary Disks: Quantifying the Growth of Circumstellar Dust
Young, edge-on circumstellar disks are uniquely valuable laboratories for the study of planet formation. In these objects, the central star is occulted from direct view, significant PSF artifacts are absent, and the disk is clearly seen as a central dust lane flanked by faint disk reflected light. The detailed morphology of these nebulae and its variation with wavelength provide crucial information on the disk internal structure and the properties of its constituent dust grains. A key observable is the slope defining the wavelength dependence of the dust scattering opacity, which becomes shallower when grain growth has taken place; multiwavelength resolved disk images are the key dataset enabling such measurements. Recent analyses of three different edge-on disks have revealed a diversity in their dust properties that is indicative of different degrees of dust grain evolution having taken place in each system. This characterization of disk grain growth, when applied comparatively to a larger sample of these objects, would enable the construction of an evolutionary sequence of young disks at successive stages on the road to planet formation. In pursuit of this goal, we have identified a sample of 15 edge-on disks previously discovered by HST or groundbased telescopes, but for which high fidelity, high spatial resolution images do not yet exist in both the optical and near-infrared. We propose broad-band multicolor imaging with NICMOS of all these targets, and ACS imaging of nine of these targets In combination with existing data, the proposed images will form a complete database of high resolution optical/near-IR images for these 15 disk systems. Scattered light modeling will be used to derive the disk structure and dust properties, yielding results that will be of fundamental importance for our understanding of grain properties during protoplanetary disk evolution.
ACS/WFC 10586
The Rosetta Stone without a Distance: Hunting for Cepheids in the Primordial Galaxy I Zw 18
The Blue Compact Dwarf galaxy I Zw 18 is one of the most intriguing objects in the Local Universe. It has the lowest nebular metallicity of all known galaxies {Z=1/32 solar}. It has long been regarded as a possible example of a galaxy undergoing its first burst of star formation. However, its real evolutionary state continues to be controversial. The WFPC2 and NICMOS detection of AGB stars by our group and others suggested the presence of an underlying older population. However, deeper ACS observations by Izotov & Thuan {2004} recently failed to detect the signature of RGB stars. This was interpreted as confirmation that I Zw 18 is in fact a galaxy “in formation”, a local analog of primordial galaxies in the distant Universe. This result was widely reported in the international news media. However, an alternative possibility is that I Zw 18 is somewhat further away than previously believed, so that Red Giant Branch stars were too faint to detect. Quoted distances in the literature have ranged from 10 to 20 Mpc. We intend to resolve this controversy by direct determination of the distance to 1 Mpc accuracy using Cepheids. For this we request 12 visits of two orbits each, to execute at carefully planned intervals. We will obtain V and I band ACS/WFC photometry in each visit. The new data will be combined with archival data, but we show that the archival data by themselves are insufficient to achieve our science goals. The distance will allow us to place I Zw 18 into its proper place in the evolutionary sequence of galaxy formation.
ACS/WFC 10569
A Last Look at the First Gravitational Lens
Strong gravitational lensing provides our best probe of the behavior of dark matter in galaxy halos and their substructure. We undertake ACS imaging to gain new strong and weak lensing data for the first-discovered lens system Q0957+561. We will make a weak lensing image spanning 6′ to map the potential of the cluster around the lens galaxy, and simultaneously obtain a deep image of more than 10 multiply-imaged features in the strong lensing region. This will complete HST’s legacy dataset for Q0957+561: a deep multicolor image of a rich multiple-image system, an extremely high-quality weak lensing map, and an existing deep NICMOS image of the Einstein ring. We will combine these three kinds of data into a single lens model–a first–to produce a sophisticated dark matter map that will provide a uniquely detailed view of the relation between visible and dark matter on galaxy scales, and the best available constraints on dark substructure. In addition, the best available $H_0$ measurement from lensing will potentially allow us to leverage the WMAP data into a more precise measurement of dark energy properties as well. Astrophysics with strong lensing depends crucially on HST’s unique capability for precise, well-resolved observations of low-surface-brightness structures next to bright objects, so it is a high priority to address outstanding questions before the demise of HST.
ACS/HRC 10544
Resovled Images of LMC Microlensing Events Observed by a Telescope at 2 AU from Earth
The identity of the lens objects for most of the LMC microlensing events seen by the MACHO Project is unknown. The most popular explanations include a previously unknown population of old, cool white dwarfs in the Galactic halo or in a very thick disk, or a variation standard LMC models that would allow most events to be caused by faint LMC stars. This uncertainty exists because it is usually impossible to determine the lens distance from the observable features of a microlensing event. Distance estimates can be obtained by measuring the microlensing parallax effect with simultaneous observations of the events from Earth and from a small {~30cm} telescope located 1-2 AU from the Earth. Such a telescope has just been launched: the High Resolution Instrument on the flyby spacecraft of the Deep Impact {DI} Mission. This telescope has been placed in an ideal orbit for LMC microlensing parallax measurements, and the telescope will be at a distance of >1 AU from Earth when the DI prime mission ends this August. Our group plans to take advantage of this fortuitous circumstance and propose a “new science” extended mission for the DI flyby spacecraft to resolve the LMC microlensing puzzle with microlensing parallax observaions. This project is compatible with the DI Science Teams extended mission plans to visit a 2nd comet, and our extended mission proposal to NASA will be written in collaboration with the Deep Impact Science team. A crucial feature of these proposed microlensing parallax measurements is the determination of the absolute brightness of the source stars, which can only be resolved with HST images. The source star brightness must be measured over the entire sensitivity range of the Deep Impact High Resolution Instrument clear filter: 300-1000nm. We therefore request UBVriz HST images to resolve the blending of the microlensed LMC source stars observed by the Deep Impact 30cm telescope.
ACS/HRC 10539
Coronagraphic Imaging of Bright New Spitzer Debris Disks
Fifteen percent of bright main sequence stars possess dusty circumstellar debris disks revealed by far-infrared photometry. These disks are signposts of planetary systems: collisions among larger, unseen parent bodies maintain the observed dust population against losses to radiation pressure and P-R drag. Images of debris disks at optical, infrared, and millimeter wavelengths have shown central holes, rings, radial gaps, warps, and azimuthal asymmetries which indicate the presence of planetary mass perturbers. Such images provide unique insights into the structure and dynamics of exoplanetary systems. Relatively few debris disks have been spatially resolved. Only nine have ever been resolved at any wavelength, and at wavelengths < 10 microns {where subarcsec resolution is available}, only seven: beta Pictoris, HR 4796, HD 141569, AU Mic, HD 107146, HD 92945, and Fomalhaut. Imaging of many other debris disk targets has been attempted with various HST cameras/coronagraphs and adaptive optics, but without success. The key property which renders a debris disk observable in scattered light is its dust optical depth. The seven disks imaged so far all have a dust excess luminosity >~ 0.01% that of the central star; no disks with smaller optical depths have been detected. Most main sequence stars known to meet this requirement have already been observed, so future progress in debris disk imaging depends on discovering additional stars with large infrared excess. The Spitzer Space Telescope offers the best opportunity in 20 years to identify new examples of high optical depth debris disk systems. We propose ACS coronagraphic imaging of nine bright, new debris disks uncovered during the first year of the Spitzer mission. Our goal is to obtain the first resolved images of these disks at ~3 AU resolution, define the disk sizes and orientations, and uncover disk substructures indicative of planetary perturbations. The results should double the number of debris disks observed at 0.06″ resolution, and open a wider window into the structure of planetary systems.
ACS/WFC/NIC3/WFPC2 10530
Probing Evolution And Reionization Spectroscopically {PEARS}
While imaging with HST has gone deep enough to probe the highest redshifts, e.g. the GOODS survey and the Ultra Deep Field, spectroscopic identifications have not kept up. We propose an ACS grism survey to get slitless spectra of all sources in a wide survey region {8 ACS fields} up to z =27.0 magnitude, and an ultradeep field in the HUDF reaching sources up to z =28 magnitude. The PEARS survey will: {1} Find and spectrocopically confirm all galaxies between z=4-7. {2} Probe the reionization epoch by robustly determining the luminosity function of galaxies and low luminosity AGNs at z = 4 – 6. With known redshifts, we can get a local measure of star formation and ionization rate in case reionization is inhomogeneous. {3} Study galaxy formation and evolution by finding galaxies in a contiguous redshift range between 4 < z < 7, and black hole evolution through a census of low-luminosity AGNs. {4} Get a robust census of galaxies with old stellar populations at 1 < z < 2.5, invaluable for checking consistency with heirarchical models of galaxy formation. Fitting these galaxies' spectra will yield age and metallicity estimates. {5} Study star-formation and galaxy assembly at its peak at 1< z < 2 by identifying emission lines in star-forming galaxies, old populations showing the 4000A break, and any combination of the two. {6} Constrain faint white dwarfs in the Galactic halo and thus measure their contribution to the dark matter halo. {7} Derive spectro-photometric redshifts by using the grism spectra along with broadband data. This will be the deepest unbiased spectroscopy yet, and will enhance the value of the multiwavelength data in UDF and the GOODS fields to the astronomical community. To this end we will deliver reduced spectra to the HST archives.
NIC2 10510
Morphology of massive early-type galaxies at z>1.2: constraining galaxy formation models
We ask for NICMOS-NIC2 H-band imaging of a sample of 10 massive early-type galaxies spectroscopically identified at 1.2
ACS/HRC/WFC 10389
ACS CCDs daily monitor – Cycle 13 – Part 2
This program consists of a set of basic tests to monitor, the read noise, the development of hot pixels and test for any source of noise in ACS CCD detectors. The files, biases and dark will be used to create reference files for science calibration. This program will be for the entire lifetime of ACS.
ACS/HRC 10259
Planetary nebulae in the SMC: a study of stellar evolution and populations in an extremely low- metallicity environment
The final phase of the evolution of low- and intermediate-mass stars, the planetary nebula {PN} ejection, is thought to largely contribute to the carbon and nitrogen enrichment in galaxies, in particular in old stellar populations. Stellar generations forming from a carbon- and nitrogen- enriched medium are a necessary condition for planetary and life formation. It is essential to understand how stars go through the process of shedding their chemically-enriched shells, and to test the predictions of stellar evolution theory on the relationship between stellar mass and elemental enrichment. Magellanic Cloud PNs are ideal probes for this study. Their abundances can be directly related to the mass of the central stars and to that of the stellar progenitor, without the great {distance and reddening} uncertainties that affect Galactic PNs. The UV lines are essential for calculating the abundances of the element related to stellar evolution {C, N, O} and to progenitor populations {e.g., Ne}. We propose to acquire UV spectroscopy of the SMC PNs whose morphology and central star properties has been previously determined by us with HST. We will derive the {C, N, O} abundance-to-mass relation, and determine the extent to which the mass of the progenitors of asymmetric PNs exceed that of symmetric PNs. We will also test the PN luminosity function, and probe cosmic recycling, in a very low-metallicity environment.
ACS/WFC 10256
Doubling the Data on the He-II Re-ionization of the Intergalactic Medium
We propose to double the existing information on the ionization of He-II in the IGM at redshifts around 3. We will observe 3 QSOs that are bright in the far UV. Each will give a moderate resolution HST spectrum better than any obtained so far. We will also observe a fourth QSO that currently lacks high SNR spectra. This program addresses a central issue in cosmology: the reionization of the intergalactic medium {IGM}. Current theoretical models predict that H I starts to reionize around z=17, completing near 6, while He-II reionization is delayed until z=3. The theoretical models of the ionization of He-II in the IGM now offer more detailed predictions that the data can distinguish. The new spectra will provide the data required to distinguish between different reionization scenarios, by increasing the number of lines of sight near z=3 with good spectra from 3 to 7, 3 of which will have the best sensitivity to the He-II optical depth. For the first time we also explore the 3-dimensional distribution of the ionizing regions, to characterize the luminosity and number density of the ionizing sources.
FLIGHT OPERATIONS SUMMARY:
Significant Spacecraft Anomalies: (The following are preliminary reports of potential non-nominal performance that will be investigated.)
HSTARS: 9964 – GSACQ(1,2,1) failed, search radius limit exceeded on FGS 2 @ 274/1125z GSACQ(1,2,1) at 274/11:25:23 failed due to Search Radius Limit Exceeded on FGS 2 at 11:28:32. OBAD prior to GSACQ had total RSS attitude error of 9.89 arcseconds, within the search radius.
GSACQ(1,2,1) at 12:56:41 with the same guide stars also failed due to Search Radius Limit Exceeded on FGS 2 at 13:00:33. OBAD prior to GSACQ had total RSS attitude error of 15.80 arcseconds.
9965 – GSACQ(1,2,2) failed, search radius limit exceeded on FGS 2 @ 275/0154z GSACQ(1,2,1) at 275/01:50:43 failed due to Search Radius Limit Exceeded on FGS 2 at 01:54:15. 1st prior OBAD to GSACQ had the following errors: V1 – -201.67, V2 – 2913.12, V3 – 2026.38, RSS – 3534.31. 2nd OBAD prior to GSACQ had the following errors: V1 – 7.40, V2 – 5.61, V3 – -6.29, RSS – 11.22, which is within the search radius.
9966 – GSACQ (1,2,1) fails @ 276/0649z Upon AOS @ 07:02:34, HST was in gyro control in M2G mode with no FGS fine lock. GSACQ (1,2,1) @ 06:49:43 occurred without telemetry. 1st OBAD occurred without telemetry. 2nd OBAD had the following errors: V1 -8.77, V2 14.64, V3 -14.08, RSS 22.13.
COMPLETED OPS REQUEST:
- 17556-0 – Genslew for proposal 10539 – slot 12 @ 273/1521z
- 17557-0 – Genslew for proposal 10539 – slot 1 @ 273/1524z
- 17558-0 – Genslew for proposal 10539 – slot 2 @ 273/1525z
- 17559-0 – Genslew for proposal 10487 – slot 3 @ 273/1616z
- 17560-0 – Genslew for proposal 10487 – slot 4 @ 273/1618z
- 17561-0 – Genslew for proposal 10487 – slot 5 @ 273/1619z
- 17562-0 – Genslew for proposal 10487 – slot 6 @ 273/1621z
- 17563-0 – Genslew for proposal 10487 – slot 7 @ 273/1622z
COMPLETED OPS NOTES: (None)
SCHEDULED SUCCESSFUL FAILURE TIMES
FGS
Gsacq 23 20 274/1125z
(HSTAR 9964)
275/0150z
(HSTAR 9965)
276/0649z
(HSTAR 9966)
FGS
Reacq 14 13 274/1256z
(HSTAR 9964)
OBAD with Maneuver 69 69
SIGNIFICANT EVENTS:
Flash Report: NICMOS NV0009 activation The NICMOS flight software, NV009 (CS FSW 5.0), was activated successfully this evening by transition the instrument to boot and back up to SAA Operate via SMS. The transition was complete at 276/0019. The transition and subsequent operations were nominal.
