NASA Hubble Space Telescope Daily Report #4299
HUBBLE SPACE TELESCOPE DAILY REPORT # 4299
– Continuing to collect World Class Science
PERIOD COVERED: UT February 13, 2007 (DOY 044)
OBSERVATIONS SCHEDULED
WFPC2 10918
Reducing Systematic Errors on the Hubble Constant: Metallicity Calibration of the Cepheid PL Relation
Reducing the systematic errors on the Hubble constant is still of significance and of immediate importance to modern cosmology. One of the largest remaining uncertainties in the Cepheid-based distance scale {which itself is at the foundation of the HST Key Project determination of H_o} which can now be addressed directly by HST, is the effect of metallicity on the Cepheid Period-Luminosity relation. Three chemically distinct regions in M101 will be used to directly measure and thereby calibrate the change in zero point of the Cepheid PL relation over a range of metallicities that run from SMC-like, through Solar, to metallicities as high as the most metal-enriched galaxies in the pure Hubble flow. ACS for the first time offers the opportunity to make a precise calibration of this effect which currently accounts for at least a third of the total systematic uncertainty on Ho. The calibration will be made in the V and I bandpasses so as to be immediately and directly applicable to the entire HST Cepheid-based distance scale sample, and most especially to the highest-metallicity galaxies that were hosts to the Type Ia supernovae, which were then used to extend the the distance scale calibration out to cosmologically significant distances.
NIC1/NIC2/NIC3 8793
NICMOS Post-SAA calibration – CR Persistence Part 4
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=3Ddate/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.
NIC3 11064
CYCLE 15 NICMOS SPECTROPHOTOMETRY CALIBRATION PROGRAM
Now that the spectrophotometric capabilities of the NICMOS grism have been established, cycle 15 observations are needed to refine the sensitivity estimates, to check for sensitivity loss with time, to improve the accuracy of the linearity correction, to improve the secondary flux standards by re-observation, and to expand the G206 data set now that the sky subtraction technique has been shown to produce useful fluxes for some of the fainter secondary standards. These faint secondary IR standards will be a significant step towards establishing flux standards for JWST, as well as for SNAP, Spitzer, and SOFIA. 1.Re- observe the 3 primary WDs GD71, G191B2b, & GD153 twice each, once at the beginning and once near the end of the 18 month cycle. To date, we have only 2 observation of each star, while the corresponding STIS data set for these primary standards ranges from 6 to 23 obs. No observations exist for GD71 or GD153 with G206, so that the current G206 sensitivity is defined solely by G191B2B. Purposes: Refine sensitivities, measure sens losses. Orbits: 2 for each of 6 visits =3D 12 2. Re-observe WD1057 = & WD1657 plus another P041C lamp-on visit to improve the scatter in the non-lin measurements per Fig. 8 of NIC ISR 2006-02. The WD stars require 2 orbits each, while the lamp-on test is done in one. The very faintest and most crucial standard WD1657 has 2 good visits already, so to substantially improve the S/N, two visits of two orbits are needed. Include G206 for P041C in the lamp-off baseline part of that orbit. Orbits: WD1057-2, WD1657-4, P041C-1 –> 7 3. Re-observe 9 secondary standards to improve S/N of the faint ones and to include G206 for all 9. BD+17 {3 obs} is not repeated in this cycle. Four are bright enough to do in one orbit: VB8, 2M0036+18, P330E, and P177D. Orbits:2*5+4=3D14 Grand Total orbits over 18 month cycle 15 is 12+6+14=3D32 {Roelof will submit the P041C lamp-on visit in a separate program.}
NIC3 11080
Exploring the Scaling Laws of Star Formation
As a variety of surveys of the local and distant Universe are approaching a full census of galaxy populations, our attention needs to turn towards understanding and quantifying the physical mechanisms that trigger and regulate the large-scale star formation rates {SFRs} in galaxies.
WFPC2 10890
Morphologies of the Most Extreme High-Redshift Mid-IR-Luminous Galaxies
The formative phase of the most massive galaxies may be extremely luminous, characterized by intense star- and AGN-formation. Till now, few such galaxies have been unambiguously identified at high redshift, restricting us to the study of low-redshift ultraluminous infrared galaxies as possible analogs. We have recently discovered a sample of objects which may indeed represent this early phase in galaxy formation, and are undertaking an extensive multiwavelength study of this population. These objects are bright at mid-IR wavelengths {F[24um]>0.8mJy}, but deep ground based imaging suggests extremely faint {and in some cases extended} optical counterparts {R~24-27}. Deep K-band images show barely resolved galaxies. Mid-infrared spectroscopy with Spitzer/IRS reveals that they have redshifts z ~ 2-2.5, suggesting bolometric luminosities ~10^{13-14}Lsun! We propose to obtain deep ACS F814W and NIC2 F160W images of these sources and their environs in order to determine kpc-scale morphologies and surface photometry for these galaxies. The proposed observations will help us determine whether these extreme objects are merging systems, massive obscured starbursts {with obscuration on kpc scales!} or very reddened {locally obscured} AGN hosted by intrinsically low-luminosity galaxies.
WFPC2 10913
The Light Echoes around V838 Monocerotis
V838 Monocerotis, which burst upon the astronomical scene in early 2002, is a completely unanticipated new object. It underwent a large-amplitude and very luminous outburst, during which its spectrum remained that of an extremely cool supergiant. A rapidly evolving set of light echoes around V838 Mon was discovered soon after the outburst, and quickly became the most spectacular display of the phenomenon ever seen. These light echoes provide the means to accomplish four unique types of measurements based on continued HST imaging during the event: {1} Study effects of MHD turbulence at high resolution and in 3 dimensions; {2} Construct the first unambiguous and fully 3-D map of a circumstellar dust envelope in the Milky Way; {3} Study dust physics in a unique setting where the spectrum and light curve of the illumination, and the scattering angle, are unambiguously known; and {4} Determine the distance to V838 Mon through direct geometric techniques. Because of the extreme rarity of light echoes, this is almost certainly the only opportunity to achieve such results during the lifetime of HST. We propose two visits during Cycle 15, in order to continue the mapping of the circumstellar dust and to achieve the other goals listed above.
WFPC2 11095
Hubble Heritage Observations of NGC 6050
The Hubble Heritage team will use a single pointing of WFPC2 to obtain F450W, F555W, F656N, and F814W images of NGC 6050 as part of a public release image.
FLIGHT OPERATIONS SUMMARY:
Significant Spacecraft Anomalies: (The following are preliminary reports of potential non-nominal performance that will be investigated.)
HSTARS:
10689 – GSacq(2,3,3) failed to RGA control
GSacq(2,3,3) scheduled at 044/17:25:14 failed at 17:29:07 due to Scan Step Limit exceeded on FGS 2. The OBAD at 17:19:58 showed errors of V1=3D2.32, V2=3D-7.92, V3=3D24.45, and RSS=3D 25.80.
10692 – GSACQ(1,2,1) failed, Search Radius Limit Exceeded on FGS 1
Upon acquisition of signal at 045:08:50:59 vehicle was in gyro control with FGS 1 search radius limit flag set. GSACQ(1,2,1) at 045:08:35:24 failed with search radius limit exceeded. OBAD map after GSACQ failure showed RSS error of 6.87 arcseconds.
COMPLETED OPS REQUEST: (None)
COMPLETED OPS NOTES: (None)
SCHEDULED SUCCESSFUL FGS GSacq 06 04 FGS REacq 08 08 OBAD with Maneuver 27 27
SIGNIFICANT EVENTS: (None)
