NASA Hubble Space Telescope Daily Report #5140
HUBBLE SPACE TELESCOPE DAILY REPORT #5140
Continuing to Collect World Class Science
PERIOD COVERED: 5am July 16 – 5am July 19, 2010 (DOY 197/09:00z-200/09:00z)
FLIGHT OPERATIONS SUMMARY:
Significant Spacecraft Anomalies: (The following are preliminary reports of potential non-nominal performance that will be investigated.)
HSTARS:
#12330 REAcq(1,2,1) @197/19:28z and 21:04z failed to RGA, Scan Step Limit on FGS1
Observations affected: COS #54-59 and ACS #120-126 Proposal #11658
COMPLETED OPS REQUEST: (None)
COMPLETED OPS NOTES: (None)
SCHEDULED SUCCESSFUL
GSAcq 25 25
FGS REAcq 24 22
OBAD with Maneuver 20 20
SIGNIFICANT EVENTS: (None)
OBSERVATIONS SCHEDULED:
WFC3/UV/ACS/WFC/IR 12057
A Panchromatic Hubble Andromeda Treasury – I
We propose to image the north east quadrant of M31 to deep limits in the UV, optical, and near-IR. HST imaging should resolve the galaxy into more than 100 million stars, all with common distances and foreground extinctions. UV through NIR stellar photometry (F275W, F336W with WFC3/UVIS, F475W and F814W with ACS/WFC, and F110W and F160W with WFC3/NIR) will provide effective temperatures for a wide range of spectral types, while simultaneously mapping M31’s extinction. Our central science drivers are to: understand high-mass variations in the stellar IMF as a function of SFR intensity and metallicity; capture the spatially-resolved star formation history of M31; study a vast sample of stellar clusters with a range of ages and metallicities. These are central to understanding stellar evolution and clustered star formation; constraining ISM energetics; and understanding the counterparts and environments of transient objects (novae, SNe, variable stars, x-ray sources, etc.). As its legacy, this survey adds M31 to the Milky Way and Magellanic Clouds as a fundamental calibrator of stellar evolution and star-formation processes for understanding the stellar populations of distant galaxies. Effective exposure times are 977s in F275W, 1368s in F336W, 4040s in F475W, 4042s in F814W, 699s in F110W, and 1796s in F160W, including short exposures to avoid saturation of bright sources. These depths will produce photon-limited images in the UV. Images will be crowding-limited in the optical and NIR, but will reach below the red clump at all radii. The images will reach the Nyquist sampling limit in F160W, F475W, and F814W.
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.
ACS/WFC 11996
CCD Daily Monitor (Part 3)
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 308 orbits (19.25 weeks) from 21 June 2010 to 1 November 2010.
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 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 11907
UVIS Cycle 17 Contamination Monitor
The UV throughput of WFC3 during Cycle 17 is monitored via weekly standard star observations in a subset of key filters covering 200-600nm and F606W, F814W as controls on the red end. The data will provide a measure of throughput levels as a function of time and wavelength, allowing for detection of the presence of possible contaminants.
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).
STIS/MA1/MA2 11857
STIS Cycle 17 MAMA Dark Monitor
This proposal monitors the behavior of the dark current in each of the MAMA detectors.
The basic monitor takes two 1380s ACCUM darks each week with each detector. However, starting Oct 5, pairs are only included for weeks that the LRP has external MAMA observations planned. The weekly pairs of exposures for each detector are linked so that they are taken at opposite ends of the same SAA free interval. This pairing of exposures will make it easier to separate long and short term temporal variability from temperature dependent changes.
For both detectors, additional blocks of exposures are taken once every six months. These are groups of five 1314s FUV-MAMA Time-Tag darks or five 3x315s NUV ACCUM darks distributed over a single SAA-free interval. This will give more information on the brightness of the FUV MAMA dark current as a function of the amount of time that the HV has been on, and for the NUV MAMA will give a better measure of the short term temperature dependence.
STIS/CC 11847
CCD Bias Monitor-Part 2
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/CC 11845
CCD Dark Monitor Part 2
Monitor the darks for the STIS CCD.
WFC3/IR 11838
Completing a Flux-limited Survey for X-ray Emission from Radio Jets
We will measure the changing flow speeds, magnetic fields, and energy fluxes in well-resolved quasar jets found in our short-exposure Chandra survey by combining new, deep Chandra data with radio and optical imaging. We will image each jet with sufficient sensitivity to estimate beaming factors and magnetic fields in several distinct regions, and so map the variations in these parameters down the jets. HST observations will help diagnose the role of synchrotron emission in the overall SED, and may reveal condensations on scales less than 0.1 arcsec.
COS/NUV/FUV 11728
The Impact of Starbursts on the Gaseous Halos of Galaxies
Perhaps the most important (yet uncertain) aspects of galaxy evolution are the processes by which galaxies accrete gas and by which the resulting star formation and black hole growth affects this accreting gas. It is believed that both the form of the accretion and the nature of the feedback change as a function of the galaxy mass. At low mass the gas comes in cold and the feedback is provided by massive stars. At high mass, the gas comes in hot, and the feedback is from an AGN. The changeover occurs near the mass where the galaxy population transitions from star-forming galaxies to red and dead ones. The population of red and dead galaxies is building with cosmic time, and it is believed that feedback plays an important role in this process: shutting down star formation by heating and/or expelling the reservoir of cold halo gas. To investigate these ideas, we propose to use COS far-UV spectra of background QSOs to measure the properties of the halo gas in a sample of galaxies near the transition mass that have undergone starbursts within the past 100 Myr to 1 Gyr. The galactic wind associated with the starburst is predicted to have affected the properties of the gaseous halo. To test this, we will compare the properties of the halos of the post-starburst galaxies to those of a control sample of galaxies matched in mass and QSO impact parameter. Do the halos of the post-starburst galaxies show a higher incidence rate of Ly-Alpha and metal absorption-lines? Are the kinematics of the halo gas more disturbed in the post-starbursts? Has the wind affected the ionization state and/or the metallicity of the halo? These data will provide fresh new insights into the role of feedback from massive stars on the evolution of galaxies, and may also offer clues about the properties of the QSO metal absorption-line systems at high-redshift .
WFC3/IR 11712
Calibration of Surface Brightness Fluctuations for WFC3/IR
We aim to characterize galaxy surface brightness fluctuations (SBF), and calibrate the SBF distance method, in the F110W and F160W filters of the Wide Field Camera 3 IR channel. Because of the very high throughput of F110W and the good match of F160W to the standard H band, we anticipate that both of these filters will be popular choices for galaxy observations with WFC3/IR. The SBF signal is typically an order of magnitude brighter in the near-IR than in the optical, and the characteristics (sensitivity, FOV, cosmetics) of the WFC3/IR channel will be enormously more efficient for SBF measurements than previously available near-IR cameras. As a result, our proposed SBF calibration will allow accurate distance derivation whenever an early-type or bulge-dominated galaxy is observed out to a distance of 150 Mpc or more (i.e., out to the Hubble flow) in the calibrated passbands. For individual galaxy observations, an accurate distance is useful for establishing absolute luminosities, black hole masses, linear sizes, etc. Eventually, once a large number of galaxies have been observed across the sky with WFC3/IR, this SBF calibration will enable accurate mapping of the total mass density distribution in the local universe using the data available in the HST archive. The proposed observations will have additional important scientific value; in particular, we highlight their usefulness for understanding the nature of multimodal globular cluster color distributions in giant elliptical galaxies.
WFC3/UVIS 11697
Proper Motion Survey of Classical and SDSS Local Group Dwarf Galaxies
Using the superior resolution of HST, we propose to continue our proper motion survey of Galactic dwarf galaxies. The target galaxies include one classical dwarf, Leo II, and six that were recently identified in the Sloan Digital Sky Survey data: Bootes I, Canes Venatici I, Canes Venatici II, Coma Berenices, Leo IV, and Ursa Major II. We will observe a total of 16 fields, each centered on a spectroscopically-confirmed QSO. Using QSOs as standards of rest in measuring absolute proper motions has proven to be the most accurate and most efficient method. HST is our only option to quickly determine the space motions of the SDSS dwarfs because suitable ground-based imaging is only a few years old and such data need several decades to produce a proper motion. The two most distant galaxies in our sample will require time baselines of four years to achieve our goal of a 30-50 km/s uncertainty in the tangential velocity; given this and the finite lifetime of HST, it is imperative that first-epoch observations be taken in this cycle. The SDSS dwarfs have dramatically lower surface brightnesses and luminosities than the classical dwarfs. Proper motions are crucial for determining orbits of the galaxies and knowing the orbits will allow us to test theories for the formation and evolution of these galaxies and, more generally, for the formation of the Local Group.
WFC3/IR 11696
Infrared Survey of Star Formation Across Cosmic Time
We propose to use the unique power of WFC3 slitless spectroscopy to measure the evolution of cosmic star formation from the end of the reionization epoch at z>6 to the close of the galaxy- building era at z~0.3.Pure parallel observations with the grisms have proven to be efficient for identifying line emission from galaxies across a broad range of redshifts. The G102 grism on WFC3 was designed to extend this capability to search for Ly-alpha emission from the first galaxies. Using up to 250 orbits of pure parallel WFC3 spectroscopy, we will observe about 40 deep (4-5 orbit) fields with the combination of G102 and G141, and about 20 shallow (2-3 orbit) fields with G141 alone.
Our primary science goals at the highest redshifts are: (1) Detect Lya in ~100 galaxies with z>5.6 and measure the evolution of the Lya luminosity function, independent of of cosmic variance; 2) Determine the connection between emission line selected and continuum-break selected galaxies at these high redshifts, and 3) Search for the proposed signature of neutral hydrogen absorption at re-ionization. At intermediate redshifts we will (4) Detect more than 1000 galaxies in Halpha at 0.5
observational goals. First, we will determine the redshift frequency dn/dz of the LLS over the column density range 16.0 < log(NHI) < 20.3 cm^-2. Second, we will measure the column density frequency distribution f(N) for the partial Lyman limit systems (PLLS) over the column density range 16.0 < log(NHI) < 17.5 cm^-2. Third, we will identify those sightlines which could provide a measurement of the primordial D/H ratio. By carrying out this survey, we can also help place meaningful constraints on two key quantities of cosmological relevance. First, we will estimate the amount of metals in the LLS using the f(N), and ground based observations of metal line transitions. Second, by determining f(N) of the PLLS, we can constrain the amplitude of the ionizing UV background at z~2 to a greater precision. This survey is ideal for a snapshot observing program, because the on-object integration times are all well below 30 minutes, and follow-up observations from the ground require minimal telescope time due to the QSO sample being bright.
WFC3/UVIS 11577
Opening New Windows on the Antennae with WFC3
We propose to use WFC3 to provide key observations of young star clusters in “The Antennae” (NGC4038/39). Of prime importance is the WFC3’s ability to push the limiting UV magnitude FIVE mag deeper than our previous WFPC2 observations. This corresponds to pushing the limiting cluster mass from ~10**5 to ~10**3 solar masses for cluster ages ~10**8 yrs. In addition, the much wider field of view of the WFC3 IR channel will allow us to map out both colliding disks rather than just the Overlap Region between them. This will be especially important for finding the youngest clusters that are still embedded in their placental cocoons. The extensive set of narrow-band filters will provide an effective means for determining the properties of shocks, which are believed to be a primary triggering mechanism for star formation. We will also use ACS in parallel with WFC3 to observe portions of both the northern and southern tails at no additional orbital cost. Finally, one additional primary WFC3 orbit will be used to supplement exisiting HST observations of the star-forming “dwarf” galaxy at the end of the southern tail. Hence, when completed we will have full UBVI + H_alpha coverage (or more for the main galaxy) of four different environments in the Antennae. In conjunction with the extensive multi- wavelength database we have collected (both HST and ground based) these observations will provide answers to fundamental questions such as: How do these clusters form and evolve? How is star formation triggered? How do star clusters affect the local and global ISM, and the evolution of the galaxy as a whole? The Antennae galaxies are the nearest example of a major disk–disk merger, and hence may represent our best chance for understanding how mergers form tremendous numbers of clusters and stars, both in the local universe and during galaxy assembly at high redshift.
STIS/CC/MA 11576
Physical Parameters of the Upper Atmosphere of the Extrasolar Planet HD209458b
One of the most studied extrasolar planet, HD209458b, has revealed both its lower and upper atmosphere thanks to HST and Spitzer observatories.
Through transmission spectroscopy technique, several atmospheric species were detected: NaI, HI, OI and CII. Using STIS archived transit absorption spectrum from 3000 to 8000 Angstrom, we obtained detailed constraints on the vertical profile of temperature, pressure and abundances (Sing et al 2008a, 2008b, Lecavelier et al. 2008b).
By observing in the NUV, from 2300 to 3100 Angstrom, we expect to obtain new constraints on the physical conditions and the chemical composition of the upper atmosphere: temperature/pressure profile up to very high in the atmosphere, abundance and condensation altitudes of new species, and new insight in the atmospheric escape and ionization state at the upper levels. The observation of four HD209458b transits with a single E230M setting will give access to many NUV atomic lines addressing these issues. The proposed observations will probe, for the first time, in details the atmosphere of a hot Jupiter, thus bench marking follow up studies.
STIS/CCD 11567
Boron Abundances in Rapidly Rotating Early-B Stars
Models of rotation in early-B stars predict that rotationally driven mixing should deplete surface boron abundances during the main-sequence lifetime of many stars. However, recent work has shown that many boron depleted stars are intrinsically slow rotators for which models predict no depletion should have occurred, while observations of nitrogen in some more rapidly rotating stars show less mixing than the models predict. Boron can provide unique information on the earliest stages of mixing in B stars, but previous surveys have been biased towards narrow- lined stars because of the difficulty in measuring boron abundances in rapidly rotating stars. The two targets observed as part of our Cycle 13 SNAP program 10175, just before STIS failed, demonstrate that it is possible to make useful boron abundance measurements for early-B stars with Vsin(i) above 100 km/s. We propose to extend that survey to a large enough sample of stars to allow statistically significant tests of models of rotational mixing in early-B stars.
WFC3/ACS/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/ACS/IR 11142
Revealing the Physical Nature of Infrared Luminous Galaxies at 0.3
