- Press Release
- Dec 8, 2022
NASA Hubble Space Telescope Daily Report #5013
HUBBLE SPACE TELESCOPE – Continuing to Collect World Class Science
DAILY REPORT #5013
PERIOD COVERED: 5am January 14 – 5am January 15, 2010 (DOY 014/10:00z-015/10:00z)
COS-GTO: Brown Dwarf Activity
COS will obtain ultraviolet spectra of a representative sample of brown dwarfs to study such questions as: (1) Is the hot gas in the outer atmospheres of young brown dwarfs heated by accretion? (2) Is the molecular hydrogen emission due to Lyman-alpha fluorescence or collisional excitation? (3) Are the older brown dwarfs without disks low mass analogs of active M dwarfs with flares and transient heating? (4) Are young brown dwarfs with disks low mass analogs of classical T Tauri stars?
CCD Dark Monitor Part 1
The purpose of this proposal is to monitor the darks for the STIS CCD.
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.
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).
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.v 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.
The Star Formation Rate In Nearby Elliptical Galaxies
Small amounts of star formation in normal elliptical galaxies are suggested by several results: some surprisingly young ages from optical line-index dating; cooling X-ray gas; and mid-IR dust emission. Previously, it was difficult to detect low levels of star formation, but UV imaging with WFPC3 will permit us to conclusively identify individual O/B stars in nearby normal ellipticals by their UV colors and magnitudes. This technique is orders of magnitude more sensitive than previous methods, allowing detections of star formation to levels of 1E-4 Msolar/yr. Proof of concept is provided by a very long UV ACS observation of M87 that revealed many O/B stars. We propose observations of four normal ellipticals where recent star formation is likely. This will yield their star formation rates and the locations of such activity.
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).
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.
UVIS L-Flats and Geometric Distortion
Multiple pointing observations of the globular cluster Omega Centauri (NGC 5139) will be used to measure the filter-dependent low frequency flat field (L-flat) corrections and stability for a key set of 10 broadband filters used by GO programs. The selected filters are F225W, F275W, F336W, F390W, F438W, F555W, F606W, F775W, F814W and F850LP. By measuring relative changes in brightness of a star over different portions of the detector, we will determine local variations in the UVIS detector response.
The broad wavelength range covered by these observations will allow us to derive the L- flat correction for the remaining wide, medium and narrow-band UVIS filters. The same data will also be used to determine and correct the geometric distortion that affects UVIS data. The broad wavelength range covered by these observations will allow us to measure the geometric distortion dependence with wavelength and filters and to provide the most appropriate correction over the entire wavelength range provided by UVIS.
FLIGHT OPERATIONS SUMMARY:
Significant Spacecraft Anomalies: (The following are preliminary reports of potential non-nominal performance that will be investigated.)
COMPLETED OPS REQUEST:
#18793-0 Eclipse Management for day 2010/015 @ 015/08:40z
COMPLETED OPS NOTES: (None)
FGS GSAcq 3 3
FGS REAcq 12 12
OBAD with Maneuver 3 3
Flash Report: Lunar solar eclipse 2010/015
OPS Request #18793 was successfully executed to configure the FSW processing of CSS data and temporarily disable Rate of Charge (ROC) safemode test during a series of moon shadows that occurred on GMT day 015 between 04:19z and 08:18z.