NASA Hubble Space Telescope Daily Report #4000
HUBBLE SPACE TELESCOPE – Continuing to collect World Class Science
DAILY REPORT #4000
PERIOD COVERED: UT November 02,03,04, 2005 (DOY 336,337,338)
OBSERVATIONS SCHEDULED
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.
ACS/HRC 10738
Earth Flats
Sky flats will be obtained by observing the bright Earth with the HRC and WFC. These observations will be used to verify the accuracy of the flats currently in the pipeline and to monitor any changes. Weekly coronagraphic monitoring is required to assess the changing position of the spots.
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.
ACS/HRC 10695
Coronagraphic Search for Disks around Nearby Stars
This is a search for debris disks around nearby G-type stars that have infrared excesses. The ACS coronagraph will be used with filter F606W.
ACS/WFC 10629
Are Field OB Stars Alone?
This SNAP program offers an inexpensive, simple program to search for low-mass companions of field OB stars. Do field OB stars exist in true isolation, as suggested by a recent Galactic study, or are they the tip of the iceberg on a small cluster of low-mass stars as predicted by the cluster mass function and stellar IMF? Short ACS/WFC V and I observations proposed here may easily resolve this issue for field OB stars in the Small Magellanic Cloud. Truly isolated OB stars represent a theoretical challenge and variation from clusters, in mode of star formation, and have important consequences for our understanding of the field stellar population in galaxies. Small clusters around the field OB stars, on the other hand, may confirm the universality of the stellar clustering law and IMF.
ACS/WFC 10626
A Snapshot Survey of Brightest Cluster Galaxies and Strong Lensing to z = 0.9
We propose an ACS/WFC snapshot survey of the cores of 150 rich galaxy clusters at 0.3 < z < 0.9 from the Red Sequence Cluster Survey {RCS}. An examination of the galaxian light in the brightest cluster galaxies, coupled with a statistical analysis of the strong-lensing properties of the sample, will allow us to contrain the evolution of both the baryonic and dark mass in cluster cores, over an unprecedented redshift range and sample size. In detail, we will use the high- resolution ACS images to measure the metric {10 kpc/h} luminosity and morphological disturbances around the brightest clusters galaxies, in order to calibrate their accretion history in comparison to recent detailed simulations of structure formation in cluster cores. These images will also yield a well-defined sample of arcs formed by strong lensing by these clusters; the frequency and detailed distribution {size, multiplicity, redshifts} of these strong lens systems sets strong constraints on the total mass content {and its structure} in the centers of the clusters. These data will also be invaluable in the study of the morphological evolution and properties of cluster galaxies over a significant redshift range. These analyses will be supported by extensive ongoing optical and near-infrared imaging, and optical spectroscopy at Magellan, VLT and Gemini telescopes, as well as host of smaller facilities.
ACS/HRC 10609
Sizes, Shapes, and SEDs: Searching for Mass Segregation in the Super Star Clusters of Nearby Starburst
We propose to investigate mass segregation and star cluster evolution and dissolution processes in Super Star Cluster {SSC} populations in a small sample of nearby starburst galaxies. ACS/HRC and NICMOS images of these nearby {d < 10 Mpc} starbursts can reveal evidence for mass segregation in the form of variations in size, shape, and color of the SSCs as a function of wavelength. The compactness of the cluster light profiles, and hence the stellar mass distributions, is a critical indicator of the likely fate of an SSC: long life and eventual evolution into a globular-like cluster, or dissolution. These observations will allow us to generate spectral energy distributions {SEDs} for a large sample of the SSCs at all ages and extinctions in each system. We will combine the SEDs with population synthesis models and existing ground- based spectra and Spitzer images to estimate ages, reddenings, and masses thus derive a more complete picture of the star-formation histories of the galaxies. For the brightest and most likely virialized among the SSCs we will also constrain their initial mass functions {IMFs} using high- resolution spectroscopy. Conclusions about IMFs from this technique require detailed information about the SSC concentration, light profiles, and virial status, which are only possible via ACS data. The proposed observations will provide an extensive and comprehensive data set for a large number of SSCs. By addressing the issues of mass segregation, evaporation, and destruction of SSC populations, the proposed observations will provide strong constraints on theories regarding the processes involved in the formation and evolution of SSCs and globular clusters. Given the dire predictions for the lifetime of HST, and its tremendous impact on the study of SSCs, we feel that the proposed observations not only are necessary and timely {even urgent} but will also be a fitting { and possibly final} addition to HST's legacy in the study of starburst SSCs.
ACS/WFC 10600
Studying the spectum of PSR B0656+14
PSR B0656+14 is the brightest intermediate-age pulsar which has been extensively studied in X- rays and optical with different instruments. The wide-band photometry of PSR B0656+14 strongly suggests the presence of spectral features between 4000 and 11, 000 A. The sensitivity and resolution of ACS/WFC opens an opportunity to study the pulsar spectrum with a higher resolution and a better S/N than it was previously possible. This will allow us to accurately measure the pulsar spectrum, confirm the spectral features and investigate their shape and strength.
ACS/WFC 10588
The Host Galaxies of Post-Starburst Quasars
We propose to use ACS to conduct a snapshot imaging survey of post-starburst quasars now being discovered in signficant numbers by the Sloan Digital Sky Survey. Post-starburst quasars are broad-lined AGN that also possess Balmer jumps and high-n Balmer absorption lines indicative of luminous stellar populations on order of 100 Myr old. These objects, representing a few percent of the z < 0.5 quasar population, may be an evolutionary stage in the transition of ultraluminous infrared galaxies into normal quasars, or a type of galaxy interaction that triggers both star formation and nuclear activity. These sources may also illustrate how black hole mass/bulge mass correlations arise. Ground-based imaging of individual poststarburst quasars has revealed merger remnants, binary systems, and single point sources. Our ACS snapshots will enable us to determine morphologies and binary structure on sub-arcsecond scales {surely present in the sample and impossible to do without HST}, as well as basic host galaxy properties. We will be looking for relationships among morphology, particularly separation of double nuclei, the starburst age, the quasar black hole mass and accretion rate, that will lead to an understanding of the triggering activity and mutual evolution. This project will bring quantitative data and statistics to the previously fuzzy and anecdotal topic of the "AGN-starburst connection" and help test the idea that post-starburst quasars are an early evolutionary stage of normal quasars.
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/HRC 10564
Resolving Ultracool White Dwarf Binaries
We propose an ACS/HRC imaging survey of the coolest white dwarfs known in order to search for binarity. Current models fail to match observed spectral energy distributions of these sub- 4000K stellar remnants, consistently predicting much lower luminosities than observed. A possible explanation is that they are binary in nature. Because these cool degenerates have no spectral features, the only way to investigate their apparent overluminosity is with very high resolution imaging, which can only be done with HST {these stars are far too faint to be observed with adaptive optics on the ground}. Optical wavelengths are ideal because the spectral energy distributions of these old degenerates peak near 600 nm. With the F435W filter we will be able to partially resolve equally luminous binaries as close as 0.02″, which corresponds to within 0.6 AU for over half of the 12 proposed target stars. The collected data will be critical in determining whether these stars represent the oldest white dwarfs in the solar neighborhood.
ACS/HRC 10545
Icy planetoids of the outer solar system
Early HST studies of satellites of Kuiper belt object focussed on the 50-200 km objects that were the largest known at the time. In the past 3 years we have discovered a population of much more rare and much larger {500-2000+ km} icy planetoids in the Kuiper belt. These objects are the largest and brightest known in the Kuiper belt and, in the era when we now know of more than 1000 Kuiper belt objects, these few planetoids are likely to be the focus of much of the research on physical properties of the outer solar system for years to come. We are currently engaged in an intensive program involving Spitzer, Keck, and other telescopes to study the physical and dynamical properties of this new population. HST is uniquely capable of addressing one parameter fundamental to completing the physical picture of these planetoids: the existence and size of any satellites. The detection and characterization of satellites to these large planetoids would allow us to address unique issues critical to the formation and evolution of the outer solar system, including the measurement of densities, internal properties, sizes and shapes of these objects, the study of binary formation as a function of primary size, and the context of the Pluto-Charon binary. For these bright objects, a satellite search takes less than a full orbit, allowing the opportunity for a new project on UV spectroscopy of the planetoids to piggyback at no added time cost. This poorly explored spectral range has the potential to show unique signatures of trapped gasses, cosmochemically important ices, and complex organic materials.
NIC3 10538
Near-IR Spectrophotometry of 2MASSWJ 1207334-393254B – An Extra-Solar Planetary Mass Companion
We propose to obtain “short” wavelength near-IR diagnostic and characterizing spectra of the very high probability candidate extra-solar giant planet {EGP} companion to 2MASSWJ 1207334- 393254 {2M1207}, a young brown dwarf and TW Hydrae Association member. Recent NICMOS camera 1 multi-band photometric imaging of the companion candidate, 0.77″ {54 AU projected} from 2M1207 – initially detected at longer wavelengths with VLT/NACO – implicate an object of several Jupiter masses based on cooling models of EGPs and the likely age of 2M1207 {~ 8 Myr}. Physical companionship of the EGP candidate with 2M1207 has been established at the 99.1% level of confidence via second-epoch NICMOS astrometric observations. Diagnostic spectra in the 0.8 to 1.9 micron region {unobtainable from the ground and overlapping the NICMOS imaging observations} will {a} critically inform on the physical nature of the EGP, {b} provide currently non-existing information to test/constrain theoretical models of EGP properties and evolution, and {c} unequivocally confirm the imaging of a bone fide EGP. Background light from 2M1207 would normally swamp the EGP spectrum with direct spectral imaging. To obviate this, we propose PSF-subtracted grism spectra of the EGP using 2M1207 as its own spectral template via two- orientation high-contrast image subtraction. The temporal stability of the HST+NICMOS PSF enables self-subtractions of targets at different field orientations resulting in contrast enhancements of 5 to 6 stellar magnitudes in the circumstellar background at ~ 0.8″ at these wavelengths. With the grism field oriented to place the EGP “above” and “below” 2M1207 {at two observational epochs} two independent spectra of the EGP will emerge from a difference image. This prototypical spectrum will serve to test and improve upon current models of young EGPs which predict flux suppression by molecular absorption in their atmospheres.
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.
ACS/HRC 10525
Characterizing the Near-UV Environment of M Dwarfs: Implications for Extrasolar Planetary Searches and Astrobiology
We propose SNAP observations with the ACS HRC PR200L prism, designed to measure the near ultraviolet emission in a sample of 107 nearby M dwarfs. The sample spans the mass range from 0.1 – 0.6 solar masses {temperature range 2200K – 4000K} where the UV energy distributions vary widely between active and inactive stars. The strength and distribution of this UV emission can have critical consequences for the atmospheres of attendant planets. Our proposed observations will provide desperately needed constraints on models of the habitability zone and the atmospheres of possible terrestrial planets orbiting M dwarf hosts, and will be used to sharpen TPF target selection. In addition, the NUV data will be used in conjunction with existing optical, FUV and X-ray data to constrain a new generation of M dwarf atmospheric models, and to explore unanswered questions regarding the dynamo generation and magnetic heating in these low-mass stars.
NIC2 10513
The very late phases of a thermonuclear supernova
A better understanding of the physics of Type Ia supernovae {SNe} is important for their use as cosmological standard candles. Late time observations of the SN light curves are poorly studied – but offers a unique way to probe the explosion models. Combining state of the art models of 3- D explosions with sophisticated spectral modeling, we can test these models against observations in a way not earlier possible. In particular, the broad band light curves are sensitive to the degree of clumping and the timing of the `infra-red catastrophe’, factors which depend on the explosion mechanism {deflagration vs. delayed detonation}. Further, these observations can probe the degree of positron trapping in the ejecta, important for both the SN ejecta and for the production of free positrons in the galaxy. Because of its small distance, favorable galaxy location and excellent ground based follow-up – SN 2003hv offers a unique opportunity to obtain the best late light curves to date. Observations in several optical and IR bands will enable us to distinguish between different model predictions.
ACS/WFC 10497
Cepheid Calibrations of the Luminosity of Two Reliable Type Ia Supernovae and a Re- determination of the Hubble Constant
We propose to determine the luminosity of two type Ia supernovae {SNe Ia}, 1995al in NGC 3021 and SN 2002fk in NGC 1309, by observing Cepheids in their spiral hosts. Modern CCD photometry yields an extremely tight Hubble diagram for SNe Ia with a precisely determined intercept {i.e., Delta H_0/H_0}. Yet, the measurement of the true Hubble constant via SNe Ia is limited by the calibration derived from problematic and unreliable SN data. Most of the SNe Ia calibrated by HST to date are significantly compromised by the systematics of photographic photometry, high reddening and SN peculiarity, and by the photometric anomolies associated with WFPC2. The extended reach of ACS now provides opportunities to more reliably calibrate SNe Ia and H_0. Our Cepheid calibration of a reliable SN Ia dataset, SN 1994ae, using ACS in Cycle 11 resulted in a 15% increase in H_0 from the value derived by the HST SN Ia Calibration Program. Yet, there remains a terribly small sample of reliable SN Ia data sets on which to base such a crucial cosmological result. SN 1995al and SN 2002fk are two of the best observed SNe Ia both with little reddening. They provide two opportunities to use ACS for placing the calibration of H_0 via SN Ia on firmer footing and potentially improve its precision.
ACS/WFC 10496
Decelerating and Dustfree: Efficient Dark Energy Studies with Supernovae and Clusters
We propose a novel HST approach to obtain a dramatically more useful “dust free” Type Ia supernovae {SNe Ia} dataset than available with the previous GOODS searches. Moreover, this approach provides a strikingly more efficient search-and-follow-up that is primarily pre- scheduled. The resulting dark energy measurements do not share the major systematic uncertainty at these redshifts, that of the extinction correction with a prior. By targeting massive galaxy clusters at z > 1 we obtain a five-times higher efficiency in detection of Type Ia supernovae in ellipticals, providing a well-understood host galaxy environment. These same deep cluster images then also yield fundamental calibrations required for future weak lensing and Sunyaev-Zel’dovich measurements of dark energy, as well as an entire program of cluster studies. The data will make possible a factor of two improvement on supernova constraints on dark energy time variation, and much larger improvement in systematic uncertainty. They will provide both a cluster dataset and a SN Ia dataset that will be a longstanding scientific resource.
FGS 10477
The Masses of the O-type Binary 15 Monocerotis
The O-type star 15 Mon {HD 47839} was recently discovered to be an astrometric and spectroscopic binary with a period of 25 years; it is the first known O-star system to bridge the observational gap between the period regimes normally probed by these techniques. An analysis of both the radial velocity curve and astrometric orbit yields the masses of the components and distance to the system. Continuing radial velocity and HST/FGS astrometric measurements will lead to a definitive orbit and yield key information about the masses of O-type stars. FGS TRANS mode measurements of separation, position angle, and magnitude difference {begun in Cycle 5} are needed to link existing speckle observations and anticipated observations with the CHARA Array optical interferometer. In addition, field astrometry measurements {FGS POS mode} will provide the proper motion, parallax, and the binary motion around the center of mass. The POS data will provide an accurate estimate of the mass ratio and an improved estimate of distance, and taken together with the spectroscopic and astrometric orbital data, we will obtain masses for both components accurate to a few percent.
NIC2/NIC1/NIC3/S/C 10465
NICMOS Autoreset Test
Test of the short term temperature ripples in the NICMOS dewar. The test consists of running the NICMOS detectors with and without the AUTORESET mode on. Orbits free of NICMOS science observations are to be used and each mode {ON/OFF} will run for approximately 24 hours. The long duration is on order to allow the temperature in the dewar to stabilize. Normal telemetry data will be sufficient for the temperature monitoring.
NIC2 10418
Morphologies and Color Gradients of Galaxies with the Oldest Stellar Populations at High Redshifts
We have isolated a sample of 9 luminous {~2L*} galaxies with the very oldest stellar populations at their respective redshifts. The galaxies have been found in radio-source fields chosen to be at the key redshifts z~1.5 and z~2.5, which allow the cleanest separation of old stellar populations from highly reddened starbursts with colors derived from standard filter combinations. Ground-based observations in excellent seeing and with adaptive optics of 3 of these galaxies indicate that all 3 are dominated by well relaxed disks of old stars, suggesting that the first large stellar systems to form in the universe were disks in which star formation proceeded extremely rapidly and efficiently. In order to test this conjecture, we are requesting NICMOS2 exposures of our sample to obtain high S/N imaging in the F160W filter to determine detailed morphologies of the old stellar population, coupled with either NICMOS2 F110W or ACS F814W exposures {depending on redshift} to determine color gradients and/or other systematic color variations that might provide clues to formation processes.
FLIGHT OPERATIONS SUMMARY:
Significant Spacecraft Anomalies: (The following are preliminary reports of potential non-nominal performance that will be investigated.)
HSTARS:
10031 – GSAcq (1,2,1) failed due to search radius limit exceeded on FGS 1 @338/1011z GSAcq (1,2,1) shceduled @ 338/10:10:51 failed due to search radius limit exceeded. Received ESB “a05” exceeded_SRL. OBAD1 showed the following errors: V1 -5736.02, V2 3370.38, V3 -2785.84, RSS 7212.64 OBAD2 showed the following errors: V1 -3.47, V2 11.85, V3 -3.71, RSS 12.90 OBAD MAP showed the following errors: V1 2.88, V2 64.55, V3 14.68, RSS 66.26
10032 – TREAcq (1,2,1) failed due to search radius limit exceeded on FGS 1 @338/1146z GSAcq (1,2,1) shceduled @ 338/10:10:51 failed due to search radius limit exceeded. Received ESB “a05” exceeded_SRL. OBAD1 showed the following errors: V1 -5736.02, V2 3370.38, V3 -2785.84, RSS 7212.64 OBAD2 showed the following errors: V1 -3.47, V2 11.85, V3 -3.71, RSS 12.90 OBAD MAP showed the following errors: V1 2.88, V2 64.55, V3 14.68, RSS 66.26
10033 – Gsacq(2,1,2) failes due to search radius limit exceeded on FGS2 @339/0439z GSacq(2,1,2) scheduled at 339/04:39:11 failed during a zoe. At AOS 05:01:30 flags were set indicating search radius limit exceeded on FGS 2. A ESB “a05” exceeded_SRL was also received. OBAD1 showed errors of V1= 271.39 V2= 885.13 V3= 138.91 RSS= 936.17. OBAD2 had errors of V1= -3.28 V2= -8.61 V3= 3.93 RSS= 10.02
COMPLETED OPS REQUEST:
17604-0 – Real Time OBAD Execution @338/1258z
COMPLETED OPS NOTES: (None)
SCHEDULED SUCCESSFUL FAILURE TIMES
FGS
GSacq 30 28
338/1011z(HSTAR#10031)
339/0439z(HSTAR#10033)
FGS
REacq 08 06
338/1016z//338/1146z (HSTAR#10032)
OBAD with Maneuver 70 70
SIGNIFICANT EVENTS: (None)
