NASA Hubble Space Telescope Daily Report #4977
HUBBLE SPACE TELESCOPE DAILY REPORT #4977
Continuing to Collect World Class Science
PERIOD COVERED: 5am November 20 – 5am November 23, 2009 (DOY 324/10:00z-327/10:00z)
OBSERVATIONS SCHEDULED
WFC3/IR 11930
IR Gain Measurement
The gain of the IR channel of WFC3 will be measured using a series of internal flat fields. Using knowledge gained from ground testing, we propose to collect flat field ramps which will be used to create photon transfer curves and give a measure of the gain. By using two filters centered at similar wavelengths but differing bandwidths, we will be able to search for any flux- dependent changes in the measure of the gain.
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/IR 11926
IR Zero Points
We will measure and monitor the zeropoints through the IR filters using observations of the white dwarf standard stars, GD153, GD71 and GD191B2B and the solar analog standard star, P330E. Data will be taken monthly during Cycle 17. Observations of the star cluster, NGC 104, are made twice to check color transformations. We expect an accuracy of 2% in the wide filter zeropoints relative to the HST photometric system, and 5% in the medium- and narrow-band filters.
WFC3/UV 11918
WFC3 UVIS Image Quality
The UVIS imaging performance over the detector will be assessed periodically (every 4 months) in two passbands (F275W and F621M) to check for image stability. The field around star 58 in the open cluster NGC188 is the chosen target because it is sufficiently dense to provide good sampling over the FOV while providing enough isolated stars to permit accurate PSF (point spread function) measurement. It is available year-round and used previously for ACS image quality assessment. The field is astrometric, and astrometric guide stars will be used, so that the plate scale and image orientation may also be determined if necessary (as in SMOV proposals 11436 and 11442). Full frame images will be obtained at each of 4 POSTARG offset positions designed to improve sampling over the detector.
This proposal is a periodic repeat (once every 4 months) of visits similar to those in SMOV proposal 11436 (activity ID WFC3-23). The data will be analyzed using the code and techniques described in ISR WFC3 2008-40 (Hartig). Profiles of encircled energy will be monitored and presented in an ISR. If an update to the SIAF is needed, (V2, V3) locations of stars will be obtained from the Flight Ops Sensors and Calibrations group at GSFC, the (V2, V3) of the reference pixel and the orientation of the detector will be determined by the WFC3 group, and the Telescopes group will update and deliver the SIAF to the PRDB branch.
The specific PSF metrics to be examined are encircled energy for aperture diameter 0.15, 0.20, 0.25, and 0.35 arcsec, FWHM, and sharpness. (See ISR WFC3 2008-40 tables 2 and 3 and preceding text.) about 20 stars distributed over the detector will be measured in each exposure for each filter. The mean, rms, and rms of the mean will be determined for each metric. The values determined from each of the 4 exposures per filter within a visit will be compared to each other to see to what extent they are affected by “breathing”. Values will be compared from visit to visit, starting with the values obtained during SMOV after the fine alignment has been performed, to see if the measures of the compactness of the PSF indicate degradation over time. The analysis will be repeated for stars on the inner part of the detector and stars on the outer part of the detector to check for differential degradation of the PSF.
As an example of the analysis, one can examine the sharpness of the F275W PSF exposures made during thermal vacuum testing (ISR WFC3 2008-40). To compare two samples, one can define the PSFs on each CCD chip as a sample of 8. The mean, rms, and rms of the mean sharpness are 0.0676, 0.0093, and 0.0035 for one chip, and 0.0701, 0.0085, and 0.0032 for the other. The difference of the means is 0.0025 and the statistical error in that difference is 0.0048, so the difference is not significant.
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).
ACS/WFC 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.
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 11844
CCD Dark Monitor Part 1
The purpose of this proposal is to monitor the darks for the STIS CCD.
STIS/CCD 11740
A Complete Optical and NIR Atmospheric Transmission Spectrum of the Exoplanet HD189733b
The hot Jupiter HD189733b offers the best exoplanet in which to perform atmospheric studies through transit spectroscopy. Here we propose STIS and NICMOS spectra to help construct a full exoplanetary transit transmission spectrum that extends over the entire optical and near-infrared range. Such a spectrum will link existing observed atmospheric features such as haze, water, and methane, providing a coherent understanding of all these reported features. With a spectrum covering many observed absorption features, the absolute pressure scale and abundances can be determined linking observed features to the actual atmospheric properties of the exoplanet.
WFC3/UV/ACS/WFC 11724
Direct Age Determination of the Local Group dE Galaxies NGC 147 and NGC 185
The origin of dwarf elliptical (dE) galaxies remains a mystery and the dE galaxies of the Local Group provide the best opportunity to study this galaxy class in detail. We propose to obtain ACS photometry of main sequence turnoff stars in the M31 dE satellites NGC 147 and NGC 185. Because these galaxies have little to no stars younger than 1 Gyr, resolving the main sequence turnoff is required to directly quantify their star formation histories. NGC 147 and NGC 185 are the only two dEs for which a clean measurement is feasible with the HST. This proposal was accepted in Cycle 15, but little data were taken before the failure of ACS. The main sequence turnoffs of NGC 147 and NGC 185 are expected to be at an apparent magnitude of V=29; we request F606W/F814W imaging one half magnitude fainter than this limit (three magnitudes fainter than the deepest previous dE observations). Quantifying the ratio of old to intermediate-age stars will allow us to discriminate between competing models of dE formation. On-going Keck/DEIMOS spectroscopy of several hundred red giant stars in each of these two dE galaxies, coupled with dynamical modeling and spectral synthesis, will complement the ACS measurement by providing information on chemical abundance patterns, dark matter content and internal dynamics. The proposed ACS data will be the first to directly quantify the onset and duration of star formation episodes in dE galaxies, and will thereby form the cornerstone in what promises to be the most comprehensive study of this class of galaxies.
WFC3/IR 11666
Chilly Pairs: A Search for the Latest-type Brown Dwarf Binaries and the Prototype Y Dwarf
We propose to use HST/NICMOS to image a sample of 27 of the nearest (< 20 pc) and lowest luminosity T-type brown dwarfs in order to identify and characterize new very low mass binary systems. Only 3 late-type T dwarf binaries have been found to date, despite that fact that these systems are critical benchmarks for evolutionary and atmospheric models at the lowest masses. They are also the most likely systems to harbor Y dwarf companions, an as yet unpopulated putative class of very cold (T < 600 K) brown dwarfs. Our proposed program will more than double the number of T5-T9 dwarfs imaged at high resolution, with an anticipated yield of ~5 new binaries with initial characterization of component spectral types. We will be able to probe separations sufficient to identify systems suitable for astrometric orbit and dynamical mass measurements. We also expect one of our discoveries to contain the first Y-type brown dwarf. Our proposed program complements and augments ongoing ground-based adaptive optics surveys and provides pathway science for JWST. 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. 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/IR 11548 Infrared Imaging of Protostars in the Orion A Cloud: The Role of Environment in Star Formation We propose NICMOS and WFC3/IR observations of a sample of 252 protostars identified in the Orion A cloud with the Spitzer Space Telescope. These observations will image the scattered light escaping the protostellar envelopes, providing information on the shapes of outflow cavities, the inclinations of the protostars, and the overall morphologies of the envelopes. In addition, we ask for Spitzer time to obtain 55-95 micron spectra of 75 of the protostars. Combining these new data with existing 3.6 to 70 micron photometry and forthcoming 5-40 micron spectra measured with the Spitzer Space Telescope, we will determine the physical properties of the protostars such as envelope density, luminosity, infall rate, and outflow cavity opening angle. By examining how these properties vary with stellar density (i.e. clusters vs. groups vs. isolation) and the properties of the surrounding molecular cloud; we can directly measure how the surrounding environment influences protostellar evolution, and consequently, the formation of stars and planetary systems. Ultimately, this data will guide the development of a theory of protostellar evolution. WFC3/IR 11166 The Mass-dependent Evolution of the Black Hole-Bulge Relations In the local universe, the masses of giant black holes are correlated with the luminosities, masses and velocity dispersions of their host galaxy bulges. This indicates a surprisingly close connection between the evolution of galactic nuclei (on parsec scales) and of stars on kpc scales. A key observational test of proposed explanations for these correlations is to measure how they have evolved over cosmic time. Our ACS imaging of 20 Seyfert 1 galaxies at z=0.37 showed them to have smaller bulges (by a factor of 3) for a given central black hole mass than is found in galaxies in the present-day universe. However, since all our sample galaxies had black hole masses in the range 10^8.0–8.5 Msun, we could only measure the OFFSET in black hole mass to bulge luminosity ratios from the present epoch. By extending this study to black hole masses another factor of 10 lower, we propose to determine the full CORRELATION of black hole mass with host galaxy properties at a lookback time of 4 Gyrs and to test mass-dependency of the evolution. We have selected 14 Seyfert galaxies from SDSS DR5 whose narrow Hbeta emission lines (and estimated nuclear luminosities) imply that they have black hole masses around 10^7 Msuns. We will soon complete our Keck spectroscopic measures of their bulge velocity dispersions. We need a 1-orbit NICMOS image of each galaxy to separate its nonstellar luminosity from its bulge and disk. This will allow us to make the first determination of the full black hole/bulge relations at z=0.37 (e.g. M-L and M-sigma), as well as a test of whether active galaxies obey the Fundamental Plane relation at that epoch. WFC3/IR 11150 Beta Pic Polarimetry with NICMOS Debris disk stars host transient dust grains that comprise a collisional cascade with sizes ranging from planetesimals to the sub-micron. In addition to the gravity of the host star and any planets present, these grains are subject to size-dependent non-gravitational forces, e.g., corpuscular drag and radiation pressure. When a steep spectrum of grain sizes prevails, such as the Dohnanyi distribution, scattered light images preferentially trace grains with dimensionless size parameter of order unity. Thus images in scattered starlight provide unique windows on the balance of forces acting on grains at a specific size. Therefore, in an A star system such as beta Pic, the near-IR is dominated by grains close to the blow out size and therefore NICMOS traces dust on hyperbolic orbits. Scattering is fundamentally polarization sensitive, and measurements that record intensity literally see only half the picture. If linear polarization is measured then the elements of the complex scattering matrix can be reconstructed. These matrix elements provide fundamental constraints on the size, composition and structure of the scatterers. Notably, polarimetry can be used to break the degeneracy between scattering asymmetry, g, and the radial dust gradient, which are otherwise covariant in an edge-on disk. Thus, we can use polarimetry to localize the parent bodies in the beta Pic disk. In beta Pic, dust is thought to originate mainly from the sublimation of cometary bodies near periastron. The irradiation of cometary material leads to sublimation and photodissociation of ices forming porous grains consisting of a matrix of refractory material. Such grains have a characteristic scattering signature in polarized light that can be distinguished from compact grains that arise from collisional erosion of asteroidal material. WFC3/ACS/IR/WFC 11142 Revealing the Physical Nature of Infrared Luminous Galaxies at 0.3< z<2.7 Using HST and Spitzer We aim to determine physical properties of IR luminous galaxies at 0.3< z<2.7 by requesting coordinated HST/NIC2 and MIPS 70um observations of a unique, 24um flux-limited sample with complete Spitzer mid-IR spectroscopy. The 150 sources investigated in this program have S(24um) > 0.8mJy and their mid-IR spectra have already provided the majority targets with spectroscopic redshifts (0.3< z<2.7). The proposed 150~orbits of NIC2 and 66~hours of MIPS 70um will provide the physical measurements of the light distribution at the rest-frame ~8000A and better estimates of the bolometric luminosity. Combining these parameters together with the rich suite of spectral diagnostics from the mid-IR spectra, we will (1) measure how common mergers are among LIRGs and ULIRGs at 0.3< z<2.7, and establish if major mergers are the drivers of z>1 ULIRGs, as in the local Universe, (2) study the co-evolution of star formation and blackhole accretion by investigating the relations between the fraction of starburst/AGN measured from mid-IR spectra vs. HST morphologies, L(bol) and z, and (3) obtain the current best estimates of the far-IR emission, thus L(bol) for this sample, and establish if the relative contribution of mid-to-far IR dust emission is correlated with morphology (resolved vs. unresolved).
WFPC3/IR 11099
A “silver bullet” for the sources of reionization
Recent discoveries of z>6 galaxies have given us the first glimpse of the Universe shortly after the era of reionization. The questions arose whether these first galaxies can be made responsible for the reionization process, and how long did it last. Neither observations nor theory provide a clean answer. In particular observations give results that are barely mutually consistent and need to be further tested. Observing high redshift (z>7) sources is in general difficult, mostly due to the high luminosity distance to these objects, and partly due to the lower expected stellar masses compared to objects at moderate redshifts.
We propose to use one of the most massive, merging cluster 1E0657-56 (z=0.295) as a cosmic telescopes to efficiently probe the high-redshift universe. The gravitational potential well of this cluster provides several magnitudes of magnification, enabling study of intrinsically lower luminosity galaxies.As we discuss in the proposal, due to its highly elongated mass distribution and ideal redshift the bullet cluster is a prime candidate for this study. We propose deep NICMOS and WFPC2 observations; with much reduced observing time compared to e.g. NICMOS UDF we expect an order of magnitude more (~5 candidates) z>7 objects. They will also likely be multiply imaged, and since the geometry of images depends upon the redshift, we will be able to confirm their nature, thereby not requiring (often prohibitive at these magnitudes) spectroscopic follow-up. This will enable us to count high-redshift sources and constrain their luminosity function; a task made possible with the help of gravitational lensing even in the pre-JWST era.
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.
FLIGHT OPERATIONS SUMMARY:
Significant Spacecraft Anomalies: (The following are preliminary reports of potential non-nominal performance that will be investigated.)
HSTARS: (None)
#12085 GSAcq(1,2,1) scheduled at 324/18:22:51z failed due search radius limit exceeded on FGS1 during LOS @324/18:29z
Observations affected: WFC3 #164-165 Proposal #11166
#12086 GSAcq(1,2,1) resulted in Fine Lock Backup (2,0,2) @325/17:49z
Observations possibly affected: WFC3 #235, 2 & 3 Proposal #11588
#12091 GSAcq(2,1,1) @326/07:55z failed to Fine Lock Backup on FGS2 during LOS
Observations possibly affected: ACS #66 Proposal #11724
#12094 GSAcq(1,2,1) failed @ 326/20:37z, and REAcq(1,2,1) failed @326/22:01z, due to Search Radius Limit Exceeded on FGS-1
Observations affected: STIS #55 Proposal #10897
COMPLETED OPS REQUEST:
#18562-1 CONTINGENCY: Continuous FGS Loss of Lock looping (Generic) @326/20:52z
COMPLETED OPS NOTES: (None)
SCHEDULED SUCCESSFUL
FGS GSAcq 21 19
FGS REAcq 22 21
OBAD with Maneuver 11 11
SIGNIFICANT EVENTS: (None)
