NASA Hubble Space Telescope Daily Report #5071

HUBBLE SPACE TELESCOPE DAILY REPORT #5071

Continuing to Collect World Class Science

PERIOD COVERED: 5am April 8 – 5am April 9, 2010 (DOY 098/09:00z-099/09:00z)

OBSERVATIONS SCHEDULED

COS/FUV 11524

COS-GTO: Warm and Hot ISM In and Near the Milky Way

COS G130M and G160M 20, 000 resolution observations will be obtained for 10 AGNs situated beyond Milky Way high velocity clouds. For all objects good O VI line profile observations exist from FUSE and high velocity O VI is detected. The COS observations will be used to obtain high quality absorption line profiles (S/N ~ 30 to 40) for C IV, Si IV and N V in the low and high velocity gas toward each AGN. The high ionization profiles of O VI (from FUSE), N V, C IV, and Si IV will be compared to low ionization profiles (O I, S II, Si II, Fe II, etc.) in order to evaluate the physical conditions and origins of the highly ionized gas in and near the Milky Way at low and high velocity. The HVCs include Complex C (four lines of sight), Complex A, WD, WB, and several negative velocity O VI HVCs. Other studies to be undertaken with this data set include studies of the physical conditions and abundances in the cool and warm HVC gas and studies of the physical conditions in low redshift IGM systems detected along the 10 lines of sight.

STIS/CC 11845

CCD Dark Monitor Part 2

Monitor the darks for the STIS CCD.

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.

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 11635

In Search of SNIb/Ic Wolf-Rayet Progenitors and Comparison with Red Supergiants (SNII Progenitors) in the Giant ScI Spiral M101

We propose to test two of the clearest predictions of the theory of evolution of massive-star evolution: 1) The formation of Wolf-Rayet stars depends strongly on these stars’ metallicity (Z), with relatively fewer WR stars forming at lower Z, and 2) Wolf-Rayet stars die as Type Ib or Ic supernovae. To carry out these tests we propose a deep, narrowband imaging survey of the massive star populations in the ScI spiral galaxy M101. Just as important, we will test the hypothesis that Superclusters like 30 Doradus are always richly populated with WR stars, and by implication that these complexes are responsible for the spectral signatures of starburst galaxies.

Our previous HST survey of the HII regions in the ScIII galaxy NGC 2403 suggested that the distribution of WR stars and RSG is a sensitive diagnostic of the recent star-forming history of these large complexes: young cores of O and WR stars are surrounded by older halos containing RSG. Theory predicts that this must change with metallicity; relatively fewer WR stars form at lower Z. A key goal of our proposal is to directly test this paradigm in a single galaxy, M101 being the ideal target. The abundance gradient across M101 (a factor of 20) suggests that relatively many more WR will be found in the inner parts of this galaxy than in the outer “suburbs”. Second, we note that WR stars are predicted to end their lives as core-collapse or pair-instability supernovae. The WR population in M101 may be abundant enough for one to erupt as a Type Ib or Ic supernova within a generation. The clear a priori identification of a WR progenitor would be a major legacy of HST. Third, we will also determine if “superclusters”, heavily populated by WR stars, are common in M101. It is widely claimed that such Superclusters produce the integrated spectral signatures of Starburst galaxies. We will be able to directly measure the numbers and emission-line luminosities of thousands of Wolf Rayet stars located in hundreds of M101 Superclusters, and correlate those numbers against the Supercluster sizes and luminosities. It is likely (but far from certain) that Supercluster sizes and emission-line luminosities are driven by their Wolf-Rayet star content. Our sample will be the largest and best-ever Supercluster/Wolf Rayet sample, an excellent local proxy for characterizing starburst galaxies’ Superclusters.

WFC3/UVIS 11903

UVIS Photometric Zero Points

This proposal obtains the photometric zero points in 53 of the 62 UVIS/WFC3 filters: the 18 broad-band filters, 8 medium-band filters, 16 narrow-band filters, and 11 of the 20 quad filters (those being used in cycle 17). The observations will be primary obtained by observing the hot DA white dwarf standards GD153 and G191-B2B. A redder secondary standard, P330E, will be observed in a subset of the filters to provide color corrections. Repeat observations in 16 of the most widely used cycle 17 filters will be obtained once per month for the first three months, and then once every second month for the duration of cycle 17, alternating and depending on target availability. These observations will enable monitoring of the stability of the photometric system. Photometric transformation equations will be calculated by comparing the photometry of stars in two globular clusters, 47 Tuc and NGC 2419, to previous measurements with other telescopes/instruments.

WFC3/UVIS 11905

WFC3 UVIS CCD Daily Monitor

The behavior of the WFC3 UVIS CCD will be monitored daily with a set of full-frame, four-amp bias and dark frames. A smaller set of 2Kx4K subarray biases are acquired at less frequent intervals throughout the cycle to support subarray science observations. The internals from this proposal, along with those from the anneal procedure (Proposal 11909), will be used to generate the necessary superbias and superdark reference files for the calibration pipeline (CDBS).

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.

FLIGHT OPERATIONS SUMMARY:

Significant Spacecraft Anomalies: (The following are preliminary reports of potential non-nominal performance that will be investigated.)

HSTARS:

FOR DOY 093

12241 – GSAcq(1,3,1) scheduled for 093:17:19:32z and REAcq(1,0,1) scheduled for 093:18:55:31z failed to fine lock backup on FGS1 due to scan step limit exceeded on FGS3.

Observations possibly affected: WFC3 168-169 Proposal ID#11903.

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

                       SCHEDULED SUCCESSFUL

FGS GSAcq               7               7

FGS REAcq               8               8

OBAD with Maneuver      4               4

SIGNIFICANT EVENTS: (None)