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Daily 3637
HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science
DAILY REPORT # 3637 PERIOD COVERED: DOYs 170-172 OBSERVATIONS SCHEDULED NIC3 9998 NICMOS Cycle 12 Grism Calibration and Standard Stars to 2.5microns This is the grism calibration proposal. NIC/NIC3/STIS/CCD 9877 A test of the foreground proximity effect at z=1.2 The diffuse UV background flux J is a crucial component for cosmological evolution models, though few determinations have been made. The proximity effect, the thinning out of the Lyman alpha forest near a sight- line's background quasar and explained at least partly by the enhanced ionization from the quasar, is a key method to measure J. A foreground proximity effect {FPE} should exist from quasars close on the sky but at different z; it can constrain J and test the enhanced ionization model. Galaxy clustering around the quasar may modify the effect, but knowing the galaxy density around the Lya forest should allow for corrections. We propose to measure the FPE at z=1.2, which is advantageous because 1} the diffuse UV flux is lower, and thus contrast with the UV flux of neighboring quasars is higher, and 2} galaxies are easier to identify at z=1.2. We have good knowledge of the physical volume we wish to study through surveys for quasars, MgII absorbers and galaxies, to constrain the redshift-dependent galaxy density along the line of sight. We will analyze the results based on pixel opacities, which is more sensitive to fluctuations in J than traditional line counting, and will compare our results with cosmological simulations to derive estimates of the UV background in the context of available physical models. NIC/NIC3 9865 The NICMOS Parallel Observing Program We propose to continue managing the NICMOS pure parallel program. Based on our experience, we are well prepared to make optimal use of the parallel opportunities. The improved sensitivity and efficiency of our observations will substantially increase the number of line-emitting galaxies detected. As our previous work has demonstrated, the most frequently detected line is Halpha at 0.7z1.9, which provides an excellent measure of current star formation rate. We will also detect star-forming and active galaxies in other redshift ranges using other emission lines. The grism observations will produce by far the best available Halpha luminosity functions over the crucial--but poorly observed--redshift range where galaxies appear to have assembled most of their stellar mass. This key process of galaxy evolution needs to be studied with IR data; we found that observations at shorter wavelengths appear to have missed a large fraction of the star-formation in galaxies, due to dust reddening. We will also obtain deep F110W and F160W images, to examine the space densities and morphologies of faint red galaxies. In addition to carrying out the public parallels, we will make the fully reduced and calibrated images and spectra available on-line, with some ground-based data for the deepest parallel fields included. STIS/CCD 9854 Anomalous Flux Ratios in Quadruple Gravitationally Lensed QSOs We propose to observe eight {8} gravitationally lensed systems which exhibit quadruple images of the background high redshift quasars. Models invoking a smooth potential fit the observed image positions accurately, in most cases better than 5 milliarcseconds. But the same models dramatically fail to predict the observed flux ratios. These anomalous flux ratios can be attributed to micro- or milli-lensing in the massive lensing halo. In this proposal, we will isolate the source of the anomalous flux ratios by using the superior resolution of HST/STIS to obtain spectrophotometric data and compare the emission line flux ratio of the QSOs to the continuum flux ratios. Due to the much larger size of the broad emission line regions, the flux ratios in the emission lines should only be affected by milli-lensing if the sub-halos are comparable or larger in projected size than the source region. That is, flux ratios observed in the QSO continuum are sensitive to substructure on all scales {both micro- and milli-lensing}, while the broad emission lines are insensitive to micro-lensing due to the larger physical size of the source emission region. This sample of eight quasars will provide the definitive evidence to distinguish between possible sources causing the observed anomalous flux ratios. NIC2 9845 NICMOS Confirmation of a Young Planetary-Mass Companion We have recently discovered a strong candidate for a planetary-mass {~10 Mjup} companion to a young Sun-like star, based on near-IR imaging and spectroscopy with the Keck and Subaru adaptive optics {AO} systems. While the ground-based data strongly suggest that the candidate has a very low effective temperature, and hence a very low mass, they are not definitive. We propose to obtain NICMOS coronagraphy to measure the companion's 1.9um water-band absorption. This feature is a distinct signature of very cool objects and is unobservable from the ground. The combined ground-based and space-based data set will determine whether the companion has a very low temperature, and hence if it is the lowest mass companion found to date by direct imaging. ACS/WFC/WFPC2 9837 Stellar Populations in the Outskirts of M33: A Unique Probe of Disk Galaxy Formation The fossil record of galaxy formation and evolution is imprinted on the structure and composition of galactic stellar populations. We have recently completed an extensive ground-based imaging survey of the low mass Local Group spiral, M33. Our analysis of the global structure of M33 suggests it is a 'pure disk' galaxy, with no discernible stellar halo. Furthermore, the disk surface brightness declines very abruptly beyond ~5 scalelengths. We propose here to obtain deep ACS imagery of two fields in the far outer disk of M33, located at 4.5 and 6 exponential scalelengths. Deep colour-magnitude diagrams reaching main sequence turn-offs of ~8 Gyr {corresponding to star formation episodes since z 1} will be constructed and used for quantitative modelling of the star formation history. State-of-the-art cosmological simulations of galaxy formation predict stars in the outer regions of galactic disks should be predominantly young-to-intermediate age. The data we propose to obtain will directly test this idea, and provide a much-needed observational constraint on the epoch at which disk galaxies were assembled. The proposed observations will provide an excellent complement to an ongoing Cycle 11 program to study the outer disk of the more massive system, M31. STIS/CCD/MA2 9807 Rotation in Jets from Young Stars: investigating NUV lines with very high Spectral Resolution Optical STIS spectra of the jets from DG Tau, RW Aur, TH 28 and LkHa 231 obtained by us {prop IDs. 7311, 9435} show systematic transverse radial velocity shifts in the region where the flow has just been accelerated and collimated {Bacciotti et al, 2002}, i.e. within about 100 AU from the source. We interpret such shifts as evidence for jet rotation. Whether YSO jets rotate is a fundamental question in star formation because it has been suggested that jets might be the way excess angular momentum is removed from the star/disk system, thereby allowing the star to accrete. In particular it is important to know if observed toroidal velocities are in agreement with predictions of magneto-centrifugal jet launching models. The limited spatial and spectral resolution of STIS in the optical however, only allows one to say qualitatively that the observed rotational velocities are in rough agreement with theory. Moreover only the resolved peripheral regions of the flow can be studied. We are proposing here to exploit the higher spatial and spectral resolution of STIS in the NUV to measure transverse jet velocity profiles. To measure the velocity profiles, we will observe the Mg II doublet at 2800 Angstrom {using the E230M echelle and the 6 X 0.2 slit transverse to the flow}. In comparison to the optical, the NUV affords us double the spatial resolution and we will be able to detect velocity differences across the jet down to 2 km/s. Not only should we be able to determine for the first time the detailed rotational velocity profile across a jet but we also expect to spatially resolve the high velocity axial core of the jet in the NUV. Finally we add that as very few NUV observations of the initial jet beam of YSO jets are available, our datasets should be a valuable contribution to the HST archive. STIS 9786 The Next Generation Spectral Library We propose to continue the Cycle 10 snapshot program to produce a Next Generation Spectral Library of 600 stars for use in modeling the integrated light of galaxies and clusters. This program is using the low dispersion UV and optical gratings of STIS. The library will be roughly equally divided among four metallicities, very low {[Fe/H] lt -1.5}, low {[Fe/H] -1.5 to -0.5}, near-solar {[Fe/H] -0.3 to 0.1}, and super-solar {[Fe/H] gt 0.2}, well-sampling the entire HR-diagram in each bin. Such a library will surpass all extant compilations and have lasting archival value, well into the Next Generation Space Telescope era. Because of the universal utility and community-broad nature of this venture, we waive the entire proprietary period. NIC3 9780 NIC3 Imaging of z~6 Candidates in a Deep ACS Parallel Field: Finding the reionizing population and their LF A fundamental cosmological question is when and how the universe was reionized. It is now generally believed that the reionization ended by z=6. There is evidence that QSO/AGN cannot provide enough photons to keep the universe ionized at that epoch. In Yan et al. {2003}, we presented a first statistically significant sample of 6.0z6.5 galaxy candidates, 30 objects in total found in a deep ACS/WFC parallel field by using the "drop-out" technique, and argued that the contamination due to possible contaminators was minimal. We concluded that young, star-forming galaxies did exist in large number as expected from our earlier work {Yan et al. 2002}, and that they could have contributed most of the reionizing photons. The candidates in our sample have a median magnitude of AB=27.4 mag, beyond the spectroscopic capability of any existing facilities. Any effort of acquiring a large sample of galaxies around z=6 will have the vast majority of candidates at such a faint brightness level. Thus near-IR imaging is the only practical way to further confirm the nature and the redshifts of these candidates until the launch of the JWST in 2010. Here we propose to use the NIC3 of the NICMOS to image 43% of our sample in the F110W and F160W bands to unambiguously confirm their nature. We will image 13-14 of our candidates with two NIC3 fields, and request 16 orbits of observation in total. With this data set, we will be able to determine the surface density of galaxies at the crucial epoch around z=6, and derive photometric redshift for our candidates. Our result will set stringent limits to the faint-end slope of the luminosity function {LF} and the star formation rate at z=6, and thus provide essential constraints to a series of questions regarding the reionization of the universe. ACS/WFC/WFPC2 9774 Young Massive Clusters in Spiral Galaxies and the Connection with Open Clusters We propose to carry out a census of star clusters in the disks of the nearby spiral galaxies NGC 45, NGC 1313, NGC 4395, NGC 5236 and NGC 7793. Using ACS, we will identify much fainter and older star clusters than possible in previous ground-based surveys, or even in HST imaging of more distant galaxies. For the first time, we will directly explore the connection between young "massive'' {or "super''} star clusters {YMCs} and lower-mass "open'' clusters in different star forming environments. We will test the universality of the luminosity- and mass functions of stellar clusters and establish whether the presence of YMCs is a result of a top-heavy cluster luminosity function, or follows from generally richer cluster systems. Our target galaxies span a range of morphological properties, surface brightness and star formation rate. Some of them are known from ground-based studies to host large numbers of YMCs while others have more modest cluster populations. However, previous ground-based data were restricted to luminous clusters younger than about 500 Myr. Here we will extend the search to clusters formed throughout the entire lifetime of each galaxy and reach clusters with properties typical of the Milky Way open clusters. This will allow us to close the gap between studies of extragalactic and Galactic disk clusters. ACS/WFC/HRC 9771 The local Hubble flow and the density field within 6 Mpc Great progress has been made recently in accurate distance measurements of nearby galaxies beyond the Local Group based on the luminosity of the tip of the red giant branch {TRGB}. Over the last three years, snapshot surveys with HST have provided us with the TRGB distances for more than a hundred nearby galaxies obtained with an accuracy of about 10%. The local velocity field within 5 Mpc exhibits a significant anisotropy which disagrees with a spherical Virgo-centric flow. The local Hubble flow is very cold, with 1-D rms deviations of ~30 km/s. Cosmological simulations with Cold Dark Matter can only realize such low dispersions with a combination of a low mean density of matter and a substantial component with negative pressure. There may be a constraint on the equation of state w=-p/rho. Our observations will concentrate on 116 galaxies whose expected distances lie within 4 - 6 Mpc, allowing us to trace a Dark Matter distribution in the Local Volume with twice the information currently available. The program is a good one for SNAP mode because the order and rate that the observations are made are not very important, as long as there is good completion over several years. ACS/HRC 9746 Binary systems in the Kuiper Belt The properties of the orbits of Kuiper belt object {KBO} satellites hold keys to fundamental insight into masses and densities of KBOs, the interaction history of the early solar system, the internal structure of distant ice-rock bodies, and even the genesis of the Pluto-Charon binary. Within the past 18 months, 9 KBO satellite systems have been discovered, allowing for the first time the possibility of characterizing a sample of KBO satellite orbital properties. We propose HRC observations to determine satellite orbits in the 6 best cases. We have carefully devised a strategy for each of these 6 systems to make maximum use of ground-based observations, previous HST observations, and the smallest possible number of new HST observations. Our proposed observations will efficiently provide highly reliable orbital solutions which are critical to achieving the scientific promise available from the study of these systems. Our strategy relies heavily on extensive Monte Carlo simulations to define optimal times of observing such that each new point obtained gives maximum leverage for refining the orbital solution. We find that with this strategy we can provide mass solutions for all 6 systems to an accuracy of better than 10% using only 25 new HST observations. This highly efficient program provides extreme scientific output with optimal use of scarce resources. ACS/HRC/WFC 9728 Tracing the History of Cosmic Expansion to z~2 with Type Ia Supernovae Type Ia supernovae {SNe Ia} provide the only direct evidence for an accelerating universe, an extraordinary result that needs the most rigorous test. The case for cosmic acceleration rests on the observation that SNe Ia at z = 0.5 are about 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 SNe Ia result attributed to grey dust or cosmic evolution of the SN Ia peak luminosity would not show this change of sign. We have obtained a toehold on this putative ``epoch of deceleration'' with SN 1997ff at z = 1.7, and 3 more at z 1 from our Cycle 11 program, all found and followed by HST. However, this is too important a test to rest on just a few objects, anyone of which could be subject to a lensed line-of-sight or misidentification. Here we propose to extend our measurement with observations of twelve SNe Ia in the range 1.0 z 1.5 or 6 such SNe Ia and 1 ultradistant SN Ia at z = 2, that will be discovered as a byproduct from proposed Treasury and DD programs. These objects will provide a much firmer foundation for a conclusion that touches on important questions of fundamental physics. NIC1/NIC2/NIC3 8792 NICMOS Post-SAA calibration - CR Persistence Part 3 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. WFPC2 10075 WFPC2 CYCLE 12 Intflat and Viflat Sweeps and Filter Rotation Anomaly Monitor Using intflat observations, this WFPC2 proposal is designed to monitor the pixel-to-pixel flatfield response and provide a linearity check. The intflat sequences, to be done once during the year, are similar to those from the Cycle 11 program 9597. The images will provide a backup database in the event of complete failure of the visflat lamp as well as allow monitoring of the gain ratios. The sweep is a complete set of internal flats, cycling through both shutter blades and both gains. The linearity test consists of a series of intflats in F555W, in each gain and each shutter. As in Cycle 11, we plan to continue to take extra visflat, intflat, and earthflat exposures to test the repeatability of filter wheel motions. WFPC2 10071 WFPC2 CYCLE 12 Supplemental Darks Part 3/3 This dark calibration program obtains 3 dark frames every day to provide data for monitoring and characterizing the evolution of hot pixels. ACS/HRC/WFC 10060 CCD Daily Monitor This program consists of basic tests to monitor, the read noise, the development of hot pixels and test for any source of noise in ACS CCD detectors. This programme will be executed once a day for the entire lifetime of ACS. ACS/SBC 10047 ACS UV Contamination Monitor A standard star field {NGC6681} is observed every three months, alternating between after and before annealing operations, through all the ACS broad band UV filters. NGC6681 hosts several UV spectro - photometric standard stars for which accurate spectra have been {and will continue to be} measured with STIS. Two SBC dark current exposures taken as the last exposure of each SBC sequence. Also, to minimize SBS turn-on/turn-off cycles and in order to check the lab flats for the SBC detector, internal observations using the deuterium lamp with F125LP are being taken inflight, following the UV monitor observations. The internal flats have been taken ~monthly since SMOV, and the degradation of the lamp has been monitored. The total exposure time to date is ~15 hours giving a total of 8600 counts/pixel. The goal is 10, 000 counts/pixel such that the resulting pipeline flat has uncertainties of ~1% due to poison counting statistics. Thus, approximately 3 additional hours of observation are required. ACS/WFC 10046 CCD Hot Pixel Annealing Hot pixel annealing will be performed once every 4 weeks. The CCD TECs will be turned off and heaters will be activated to bring the detector temperatures to about +20C. This state will be held for approximately 12 hours, after which the heaters are turned off, the TECs turned on, and the CCDs returned to normal operating condition. To assess the effectiveness of this procedure, a bias and two dark images will be taken after the annealing procedure for both WFC and HRC. The HRC darks are taken in parallel with the WFC darks. STIS/CCD 10037 STIS Cycle 12 Faint Standard Extension: FASTEX WD 1657+343 is the faintest of four pure hydrogen WD stars that comprised the original FASTEX program and has been observed thrice in 2000 and once in 2002 to firmly establish the absolute flux levels. Annual revisits of one orbit should occur to monitor our predictions of the CTE correction, which is increasing with time on orbit. G430L at both the standard and E1 aperture position are required at the exposure times already established as standard. The remaining time in the orbit will be spent extending the wavelength coverage using G750L. To date, HST has not provided any faint solar analog stars to compliment the three V=12-13.5 mag solar analogs provided by M. Rieke for NICMOS calibration. As instrumentation in space and on the ground becomes more sensitive, fainter flux standards are required. A solar analog in a field with low reddening is an excellent choice for a fainter standard, because unreddened pure hydrogen WDs are rare beyond V=16, because Solar absolute fluxes are well measured at all wavelengths, and because the fluxes do not fall off as fast as the hot WDs at longer wavelengths. A 16.5 G star may not be faint enough for most JWST modes but will provide a significant step in the right direction. The SNAP program requires such a spectrophotometric standard, which lies at the bright limit of its spectroscopy mode. NICMOS grism observation of this standard are planned for cycle 12 and STIS spectra are required to establish the standard over the full range from 0.3-2 microns. STIS/CCD 10020 CCD Bias Monitor - Part 2 Monitor the bias in the 1x1, 1x2, 2x1, and 2x2 bin settings at gain=1, and 1x1 at gain = 4, to build up high-S/N superbiases and track the evolution of hot columns. STIS/CCD 10018 CCD Dark Monitor-Part 2 Monitor the darks for the STIS CCD. ACS/HRC/WFC 10004 The Physics of Relativistic Jets: Chandra Imaging of Extended Jets in Gamma-loud Blazars Extended jets have been a key target for Chandra yet only recently has the kpc-scale jet physics been compared to that of the inner, parsec-scale jets. Such a comparison reveals the jet deceleration, power dissipation, pressure gradient, and confinement mechanism --- all essential ingredients for understanding the relativistic jets that characterize radio- loud AGN. Currently, few data exist to make this comparison. We propose to double the sample, with Chandra observations of 4 gamma-loud blazars: 0954+556 and 1229-021, the only 2 bright radio jets not yet observed by Chandra; and 0208-512 and 3C 454.3, observed in A03 with much too short exposures. We also propose HST multi-band ACS imaging of jet knots in 0208-512, 0954+556 and 3C 454.3. FLIGHT OPERATIONS SUMMARY: Significant Spacecraft Anomalies: (The following are preliminary reports of potential non-nominal performance that will be investigated.) HSTAR 9451: GS Acquisition (1,2,2) @ 171/08:42Z failed to RGA control due to SRLE on FGS 1. Prior FHST FM Updates showed ATT ERR of V1 = -0.701, V2 = 11.243. V3 = -13.929 and V1 = -1.629, V2 = 0.418, V3 = -2.164. The FHST Map @ 171/09:22:25Z showed attitude vehicle axis errors of 2.517, -2.027, 8.720 arcsec. Under investigation. COMPLETED OPS REQs: 17198-0 FHST Intensity Data Collection (See comment section) @170/1302z 17199-1 FHST Rate Control Data Collection (See comment section) 170/1623z OPS NOTES EXECUTED: 1245-0 Change Limits MAMA1 Threshold Voltage @171/1550z(closed @172/2335z) SCHEDULED SUCCESSFUL FAILURE TIMES FGS GSacq 25 24 171/0847z (HSTAR 9451) FGS REacq 18 18 FHST Update 47 47 LOSS of LOCK SIGNIFICANT EVENTS: The third and final group of FHST Intensity and Rate Control Data collections were successfully completed per Ops Request 17198 and 17199-1@ 170/13:02Z and 16:23Z, respectively. Sections K and L, of the consolidated script, were executed collecting one additional Intensity period and one additional Rate Control period. |
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