NASA Hubble Space Telescope Daily Report #4973
HUBBLE SPACE TELESCOPE DAILY REPORT #4973
Continuing to Collect World Class Science
PERIOD COVERED: 5am November 16 – 5am November 17, 2009 (DOY 320/10:00z-321/10:00z)
OBSERVATIONS SCHEDULED
ACS/WFC 11338
Continued M31 Monitoring for Black Hole X-ray Nova
During A01-7 we found >16 Black Hole X-ray Novae (BHXN) in M31 using Chandra, and with HST followup have estimated orbital periods for 6 of these. Observations are underway with HST to attempt to estimate additional periods. We propose to continue this program, concentrating our scarce HST resources on a single transient which exceeds the NS Eddington limit. Only uninterrupted monitoring can yield the duty cycles and long-term lightcurves of BHXN (and other variables) in M31. Our GO+GTO programs have accumulated 300ks (ACIS) near the M31 bulge, and total ACIS exposure on M31 is now 620ks. Our monitoring program alone can amass 500ks on the bulge if continued through AO12, and combined with other programs will reach >1Msec ACIS exposure on the bulge.
STIS/CCD 11879
CCD Daily Monitor (Part 1)
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 352 orbits (22 weeks) from 31 August 2009 to 31 January 2010.
COS/FUV 11895
FUV Detector Dark Monitor
The purpose of this proposal is to monitor the FUV detector dark rate by taking long science exposures without illuminating the detector. The detector dark rate and spatial distribution of counts will be compared to pre-launch and SMOV data in order to verify the nominal operation of the detector. Variations of count rate as a function of orbital position will be analyzed to find dependence of dark rate on proximity to the SAA. Dependence of dark rate as function of time will also be tracked.
COS/NUV 11894
NUV Detector Dark Monitor
The purpose of this proposal is to measure the NUV detector dark rate by taking long science exposures with no light on the detector. The detector dark rate and spatial distribution of counts will be compared to pre-launch and SMOV data in order to verify the nominal operation of the detector. Variations of count rate as a function of orbital position will be analyzed to find dependence of dark rate on proximity to the SAA. Dependence of dark rate as function of time will also be tracked.
WFC3/IR 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.
STIS/CCD 10897
Coronagraphic imaging of the submillimeter debris disk of a 200Myr old M-dwarf
A recent sub-millimeter survey has unambiguously discovered a new debris disk around the M0.5 dwarf GJ842.2 which is 200 Myr old. Reanalysis of the IRAS data has shown that there is also a 25 micron excess toward this star indicating warm dust close to the star. It is also only the second debris disk found among M-dwarfs that constitute 70 % of the stars in the Galaxy. Collisional and Poynting-Roberston timescale arguments indicate that the cold grains detected in the sub-mm are “primordial”, i.e. original grains from the protoplanetary phase. The disk around GJ842.2 is thus unique in terms of the presence of dust at such a late stage of evolution and presents two conundrums: why did it retain so much primordial dust at large distances, and why does it continue to produce dust close to the star? We propose to conduct high contrast NICMOS coronagraphic imaging of GJ842.2 to determine the spatial distribution of the small reflecting grains and test the various scenarios which might explain the IRAS and sub-mm data e.g.resonant trapping of dust by planets or “sandblasting” by interstellar medium grains working more aggressively on a low-luminosity star than on an A-type star like Beta Pic. Also, we would search for an evolutionary sequence between GJ842.2 and the only other M-dwarf with a disk resolved by HST, the 10 Myr old AU Mic system.
S/C 12046
COS FUV DCE Memory Dump
Whenever the FUV detector high voltage is on, count rate and current draw information is collected, monitored, and saved to DCE memory. Every 10 msec the detector samples the currents from the HV power supplies (HVIA, HVIB) and the AUX power supply (AUXI). The last 1000 samples are saved in memory, along with a histogram of the number of occurrences of each current value.
In the case of a HV transient (known as a “crackle” on FUSE), where one of these currents exceeds a preset threshold for a persistence time, the HV will shut down, and the DCE memory will be dumped and examined as part of the recovery procedure. However, if the current exceeds the threshold for less than the persistence time (a “mini-crackle” in FUSE parlance), there is no way to know without dumping DCE memory. By dumping and examining the histograms regularly, we will be able to monitor any changes in the rate of “mini-crackles” and thus learn something about the state of the detector.
STIS/CCD 11844
CCD Dark Monitor Part 1
The purpose of this proposal is to monitor the darks for the STIS CCD.
STIS/CCD 11846
CCD Bias Monitor-Part 1
The purpose of this proposal is to 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/CCD 11852
STIS CCD Spectroscopic Flats C17
The purpose of this proposal is to obtain pixel-to-pixel lamp flat fields for the STIS CCD in spectroscopic mode.
STIS/CCD 11855
STIS/CCD Spectroscopic Sensitivity Monitor for Cycle 17
The purpose of this proposal is to monitor the sensitivity of each CCD grating mode to detect any changes due to contamination or other causes.
WFC3/UVIS 11360
Star Formation in Nearby Galaxies
Star formation is a fundamental astrophysical process; it controls phenomena ranging from the evolution of galaxies and nucleosynthesis to the origins of planetary systems and abodes for life. The WFC3, optimized at both UV and IR wavelengths and equipped with an extensive array of narrow-band filters, brings unique capabilities to this area of study. The WFC3 Scientific Oversight Committee (SOC) proposes an integrated program on star formation in the nearby universe which will fully exploit these new abilities. Our targets range from the well-resolved R136 in 30 Dor in the LMC (the nearest super star cluster) and M82 (the nearest starbursting galaxy) to about half a dozen other nearby galaxies that sample a wide range of star-formation rates and environments. Our program consists of broad band multiwavelength imaging over the entire range from the UV to the near-IR, aimed at studying the ages and metallicities of stellar populations, revealing young stars that are still hidden by dust at optical wavelengths, and showing the integrated properties of star clusters. Narrow-band imaging of the same environments will allow us to measure star-formation rates, gas pressure, chemical abundances, extinction, and shock morphologies. The primary scientific issues to be addressed are: (1) What triggers star formation? (2) How do the properties of star-forming regions vary among different types of galaxies and environments of different gas densities and compositions? (3) How do these different environments affect the history of star formation? (4) Is the stellar initial mass function universal or determined by local conditions?
WFC3/IR 11202
The Structure of Early-type Galaxies: 0.1-100 Effective Radii
The structure, formation and evolution of early-type galaxies is still largely an open problem in cosmology: how does the Universe evolve from large linear scales dominated by dark matter to the highly non-linear scales of galaxies, where baryons and dark matter both play important, interacting, roles? To understand the complex physical processes involved in their formation scenario, and why they have the tight scaling relations that we observe today (e.g. the Fundamental Plane), it is critically important not only to understand their stellar structure, but also their dark-matter distribution from the smallest to the largest scales. Over the last three years the SLACS collaboration has developed a toolbox to tackle these issues in a unique and encompassing way by combining new non-parametric strong lensing techniques, stellar dynamics, and most recently weak gravitational lensing, with high-quality HUBBLE SPACE TELESCOPE imaging and VLT/Keck spectroscopic data of early-type lens systems. This allows us to break degeneracies that are inherent to each of these techniques separately and probe the mass structure of early-type galaxies from 0.1 to 100 effective radii. The large dynamic range to which lensing is sensitive allows us both to probe the clumpy substructure of these galaxies, as well as their low-density outer haloes. These methods have convincingly been demonstrated, by our team, using smaller pilot-samples of SLACS lens systems with HST data. In this proposal, we request observing time with WFC3 and NICMOS to observe 53 strong lens systems from SLACS, to obtain complete multi-color imaging for each system. This would bring the total number of SLACS lens systems to 87 with completed HST imaging and effectively doubles the known number of galaxy-scale strong lenses. The deep HST images enable us to fully exploit our new techniques, beat down low-number statistics, and probe the structure and evolution of early- type galaxies, not only with a uniform data-set an order of magnitude larger than what is available now, but also with a fully-coherent and self-consistent methodological approach!
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 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/UVIS 11903
UVIS Photometric Zero Points
This proposal obtains the photometric zero points in 53 of the 62 UVIS/WFC3 filters: the 18 broad-band filters, 8 medium-band filters, 16 narrow-band filters, and 11 of the 20 quad filters (those being used in cycle 17). The observations will be primary obtained by observing the hot DA white dwarf standards GD153 and G191-B2B. A redder secondary standard, P330E, will be observed in a subset of the filters to provide color corrections. Repeat observations in 16 of the most widely used cycle 17 filters will be obtained once per month for the first three months, and then once every second month for the duration of cycle 17, alternating and depending on target availability. These observations will enable monitoring of the stability of the photometric system. Photometric transformation equations will be calculated by comparing the photometry of stars in two globular clusters, 47 Tuc and NGC 2419, to previous measurements with other telescopes/instruments.
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).
FLIGHT OPERATIONS SUMMARY:
Significant Spacecraft Anomalies: (The following are preliminary reports of potential non-nominal performance that will be investigated.)
HSTARS:
12075 – GSAcq(1,2,1) failed to RGA hold due to search radius limit exceeded during LOS @ 320/11:05:25z
Observations affected: COS 5-6 Proposal ID# 11895, STIS 5 Proposal ID# 10897, STIS 6-8 Proposal ID# 11846, STIS 9-10 Proposal ID# 11852
12076 – GSAcq(1,2,1) scheduled at 320/23:40:28, REAcq(1,2,1) scheduled at 321/00:57:00z and at 321/02:38:47z all failed to gyro control due to search radius limit exceeded on FGS-1.
Observations affected: WFC3 39-46 Proposal ID# 11360.
12077 – GSAcq (2,3,3) failed to RGA Hold due to Search Radius Limit Exceeded on FGS-2 during LOS @ 321/04:54:44z.
Ops Request 18762 executed @ 321/05:46z resulted in successful REAcq (2,3,3) @ 321/06:02:14z.
Observations affected: WFC3 47-50 Proposal ID# 11360, ACS 17 Proposal ID# 11360.
COMPLETED OPS REQUEST:
18562-1 – CONTINGENCY: Continuous FGS Loss of Lock looping @ 320/1146z & 321/05:46z 18762-0 – Realtime OBAD with Correction @ 321/05:46z
COMPLETED OPS NOTES: (None)
SCHEDULED SUCCESSFUL
FGS GSAcq 10 07
FGS REAcq 06 04
OBAD with Maneuver 04 04
SIGNIFICANT EVENTS: (None)
