Status Report

NASA Hubble Space Telescope Daily Report #4280

By SpaceRef Editor
January 19, 2007
Filed under , ,
NASA Hubble Space Telescope Daily Report #4280
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HUBBLE SPACE TELESCOPE DAILY REPORT # 4280

– Continuing to collect World Class Science

PERIOD COVERED: UT January 17, 2007 (DOY 017)

OBSERVATIONS SCHEDULED

ACS/HRC 10833

Host Galaxies of Reverberation Mapped AGNs We propose to obtain unsaturated high-resolution images of 17 reverberation-mapped active galactic nuclei in order to remove the point-like nuclear light from each image, thus yielding a “nucleus-free” image of the host galaxy. This will allow investigation of host galaxy properties: our particular interest is determination of the host-galaxy starlight contribution to the reverberation-mapping observations. This is necessary {1} for accurate determination of the relationship between the AGN nuclear continuum flux and the size of the broad Balmer-line emitting regions of AGNs, which is important in estimating black hole masses for large samples of QSOs, and {2} for accurate determination of the bolometric luminosity of the AGN proper. Through observations in Cycles 12 and 14, we have obtained or will obtain images of 18 of the 35 objects in the reverberation-mapping compilation of Peterson et al. {2004}. These observations revealed that the host-galaxy contribution, even in the higher-luminosity AGNs, is higher than expected and that all of the reverberation-mapped AGNs will have to be observed, not just the lower-luminosity sources; each source is different, and each source is important. Therefore we request time to observe the 17 remaining reverberation-mapped AGNs.

ACS/HRC 11041

ACS CCDs daily monitor

This program consists of a set of basic tests to monitor, the read noise, the development of hot pixels and test for any source of noise in ACS CCD detectors. The files, biases and dark will be used to create reference files for science calibration. This programme will be for the entire lifetime of ACS. For cycle 15 the program will cover 18 months 12.1.06->05.31.08 and it has been divied into three different proposal each covering six months. The three proposals are 11041-11042-11043.

ACS/SBC 10862

Comprehensive Auroral Imaging of Jupiter and Saturn during the International Heliophysical Year

A comprehensive set of observations of the auroral emissions from Jupiter and Saturn is proposed for the International Heliophysical Year in 2007, a unique period of especially concentrated measurements of space physics phenomena throughout the solar system. We propose to determine the physical relationship of the various auroral processes at Jupiter and Saturn with conditions in the solar wind at each planet. This can be accomplished with campaigns of observations, with a sampling interval not to exceed one day, covering at least one solar rotation. The solar wind plasma density approaching Jupiter will be measured by the New Horizons spacecraft, and a separate campaign near opposition in May 2007 will determine the effect of large-scale variations in the interplanetary magnetic field {IMF} on the Jovian aurora by extrapolation from near-Earth solar wind measurements. A similar Saturn campaign near opposition in Jan. 2007 will combine extrapolated solar wind data with measurements from a wide range of locations within the Saturn magnetosphere by Cassini. In the course of making these observations, it will be possible to fully map the auroral footprints of Io and the other satellites to determine both the local magnetic field geometry and the controlling factors in the electromagnetic interaction of each satellite with the corotating magnetic field and plasma density. Also in the course of making these observations, the auroral emission properties will be compared with the properties of the near-IR ionospheric emissions {from ground-based observations} and non thermal radio emissions, from ground-based observations for Jupiter?s decametric radiation and Cassini plasma wave measurements of the Saturn Kilometric Radiation {SKR}.

ACS/WFC 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.

ACS/WFC/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.

NIC1/NIC2/NIC3 8794

NICMOS Post-SAA calibration – CR Persistence Part 5

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.

NIC2, ACS/WFC 10802

SHOES-Supernovae, HO, for the Equation of State of Dark energy

The present uncertainty in the value of the Hubble constant {resulting in an uncertainty in Omega_M} and the paucity of Type Ia supernovae at redshifts exceeding 1 are now the leading obstacles to determining the nature of dark energy. We propose a single, integrated set of observations for Cycle 15 that will provide a 40% improvement in constraints on dark energy. This program will observe known Cepheids in six reliable hosts of Type Ia supernovae with NICMOS, reducing the uncertainty in H_0 by a factor of two because of the smaller dispersion along the instability strip, the diminished extinction, and the weaker metallicity dependence in the infrared. In parallel with ACS, at the same time the NICMOS observations are underway, we will discover and follow a sample of Type Ia supernovae at z > 1. Together, these measurements, along with prior constraints from WMAP, will provide a great improvement in HST’s ability to distinguish between a static, cosmological constant and dynamical dark energy. The Hubble Space Telescope is the only instrument in the world that can make these IR measurements of Cepheids beyond the Local Group, and it is the only telescope in the world that can be used to find and follow supernovae at z > 1. Our program exploits both of these unique capabilities of HST to learn more about one of the greatest mysteries in science.

NIC3 10861

An ACS Treasury Survey of the Coma cluster of galaxies

We propose to use the unique spatial resolution of HST and ACS to construct a Treasury imaging survey of the core and infall region of the richest local cluster, Coma. We will observe samples of thousands of galaxies down to magnitude B=27.3 with the aim of studying in detail the dwarf galaxy population which, according to hierarchical models of galaxy formation, are the earliest galaxies to form in the universe. Our initial scientific objectives are: 1} A study of the structure of the dwarf galaxies, including scaling laws, nuclear structure and morphology, to compare with hierarchical and evolutionary models of their formation. 2} A study of the stellar populations from colors and color gradients, and how the internal chemical evolution of galaxies is affected by interaction with the cluster gaseous and galaxy environment. 3} To determine the effect of the cluster environment upon morphological features, disks, bulges and bars, by comparing these structure in the Coma sample with field galaxy samples. 4} Identification of dwarf galaxy samples for further study with the new generation of multi-object and integral-field spectrographs on 8-10 metre class telescopes such as Keck, Subaru, Gemini, and GTC. This is the first such survey of a nearby rich cluster. It will provide a key database for studies of galaxy formation and evolution, and a very needed reference for comparison with similar galaxy surveys both in lower density environments in the nearby universe, and in high density environments at high redshifts.

FLIGHT OPERATIONS SUMMARY:

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

HSTARS: (None)

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

                       SCHEDULED      SUCCESSFUL 
FGS GSacq             10                      10 
FGS REacq              05                  05 
OBAD with Maneuver 30                      30 

SIGNIFICANT EVENTS: (None)

SpaceRef staff editor.