| PI Name | Title | Chandra time | Targets |
|---|---|---|---|
| Joel Bregman | Ultraluminous X-Ray Sources and Intermediate Mass Black Holes | 3 ks | NGC4559 |
| S. George Djorgovski | A Snapshot Survey of the Optically Selected Type-2 Quasars | 25 ks | Approved for a maximum of five targets, and a maximum of 5 ksec per target, with the additional condition that Chandra observations will be scheduled and executed only for those targets for which HST observations have been obtained successfully, as part of the present snapshot program, before June 30, 2002. |
| Harald Ebeling | Measuring the mass distribution in the most distant, very X-ray luminous galaxy cluster known | 32 ks | CLJ1226.9+3332 |
| Mike Gladders | A New High-z Galaxy Cluster with Extraordinary Lensed Arcs From Multiple Sources | 15 ks | RCS0224-0002 |
| Gerard Kriss | Simultaneous HST, Chandra and FUSE Observations of Intrinsic Absorbers in AGN | 80 ks | NGC7469 |
| S. R. Kulkarni | Gamma-ray burst progenitors: probing their environment | 55 ks | 1 TOO |
| Karen Leighly | Exploratory Observations of a New Bright Quasar | 20 ks | PHL 1811 |
| Raghvendra Sahai | A YSO-like pulsed astrophysical jet and bipolar nebula in a dying star: WFPC2/STIS study of He2-90 | 10 ks | He2-90 |
| Meg Urry | The Physics of X-Ray/Optical Jets | 80 ks | 3C371.0 and PKS2201+044 |
| William Welsh | Flares, Magnetic Reconnections and Accretion Disk Viscosity | 25 ks | EM-CYG |
================================================================================ PI: Karen Leighly Proposal Title: Exploratory Observations of a New Bright Quasar Approved Chandra Time (Ksecs): 20 Scientific Category: AGN/QUASARS Abstract The VLA FIRST radio survey recently discovered a new, extremely bright quasar that is the second brightest optical object in the sky at z > 0.1. Optically classified as a Narrow-line Seyfert 1 galaxy (NLS1), PHL 1811 is not typical of this class of objects because it is a very weak X-ray source. We propose short exploratory UV spectroscopic observations of this new bright quasar that will reveal its true nature and permit us to identify potential applications of future deeper observations. PHL 1811 may be the brightest luminous NLS1, in which case the study of the profiles and ratios of the emission lines will be valuable. Alternatively, PHL 1811 may be the brightest BALQSO, and the structure and composition of the BAL flow may be studied. PHL 1811 may be a useful probe for local LyAlpha absorption and follow-up high resolution spectroscopy will be indicated; furthermore, the proposed HST STIS observation will support the FUSE observation scheduled for this fall. We also request short Chandra observations to identify the origin of the faint X-ray emission. ================================================================================
PI: Gerard Kriss
Proposal Title: Simultaneous HST, Chandra and FUSE Observations of Intrinsic
Absorbers in AGN
Approved Chandra Time (Ksecs): 80
Scientific Category: AGN/QUASARS
Abstract
Photoionized, warm absorbing gas is an important component of the nuclear
structure of AGN. Approximately half of all low-z AGN show high-ionization
UV absorption lines and X-ray warm absorbers, but the relationship of the
UV-absorbing gas to the even higher ionization X-ray absorbing material is
not yet understood. Only a handful of high-spectral-resolution
observations with HST, Chandra or FUSE currently exist (NGC 4151, NGC
3516, NGC 3783, NGC 5548, Mrk 509). These show a diversity of kinematic
structure and ionization states in the absorbers. We propose to increase
significantly the sample of low-redshift AGN studied at high spectral
resolution in the UV and the X-ray by obtaining simultaneous HST,
Chandra, and FUSE spectra of NGC 7469 and Mrk 279. Both are bright AGN
with O vi absorption resolved in recent FUSE observations. The new
simultaneous observations will resolve the kinematics and ionization state
of both the UV and X-ray absorbers. This will permit a definitive
assessment of their relationship and give clues to their location in the
nuclear region. Using the variety of ionization states and the multiple
absorbing components, we will also reconstruct the ionizing spectrum.
Understanding the absorbing gas and its influence on the radiation
escaping from AGN has important implications for the radiative input to
the IGM and the origins of the X-ray background.
================================================================================
PI: S. George Djorgovski Proposal Title: A Snapshot Survey of the Optically Selected Type-2 Quasars Approved Chandra Time (Ksecs): 25 Scientific Category: AGN/QUASARS Abstract We identified a population of emission-line objects in DPOSS, which can be plausibly interpreted as the long-sought type-2 quasars. They have high- ionization Seyfert-2 like spectra, but with narrow-line luminosities comparable to those of the luminous type-1 quasars in the same redshift range. Keck spectropolarimetry confirms the presence of hidden QSO nuclei in them. This provides a major piece of evidence in favor of the unified schemes for AGN, and it should help extend our understanding of AGN in general. This population may be a major contributor to the cosmic hard x- ray background. It is complementary to the optically dull hard x-ray sources found by Chandra. We propose to obtain multi-color images of a representative sample of these objects, in order to examine their morphology with the superior angular resolution of the HST. We may be able to detect point-like nuclei which are not detectable in ground-based images, the dust lanes hiding them from our view, possible evidence for tidal interactions and the overall morphology of their hosts, etc. We also propose for Chandra observations for a subsample of 5 objects, in order to probe the column densities of the obscuring material and to constrain their bolometric luminosities. This study would greatly increase our understanding of these objects, which are an important missing link in the overall picture of AGN populations in the universe. ================================================================================
PI: Meg Urry Proposal Title: The Physics of X-Ray/Optical Jets Approved Chandra Time (Ksecs): 80 Scientific Category: AGN/QUASARS Abstract An important new probe of the physics of large-scale radio jets is possible with the discovery of resolved X-ray/optical jets. The optical emission comes from high energy electrons, which have short radiative lifetimes and so pinpoint particle acceleration sites. Spectral energy distributions of knots in two jets suggest the X-rays come from lower energy electrons inverse-Compton scattering the (beamed) cosmic microwave background. This requires the jet to be still relativistic on kiloparsec scales (out to ~1 Mpc for the high-redshift jets!). This model robustly constrains both the bulk relativistic speed and the minimum electron energy in the jet, which together determine the total jet power. To probe jet energetics and physics generally, and to test the ``Compton/CMB'' interpretation specifically, we propose deep HST imaging of three X- ray/optical jets (PKS 1127--145, PKS 0637--752, 3C 371) and one optical jet (PKS 2201+044), plus Chandra observations of the latter two. The multiwavelength spectra of individual knots differ significantly, as does one jet from another, indicating the need for detailed high-resolution study of more than 1 or 2 jets. Along with the well-observed 3C 273 and M 87 jets, the 4 proposed targets are the only known (or likely) nonthermal X-ray jets readily detected with Chandra and HST.
================================================================================
PI: Harald Ebeling
Proposal Title: Measuring the mass distribution in the most distant, very X-ray
luminous galaxy cluster known
Approved Chandra Time (Ksecs): 32
Scientific Category: COSMOLOGY
Abstract
We propose to obtain a mosaic of deep HST/WFPC2 images to conduct a weak
lensing analysis of the mass distribution in the massive, distant galaxy
cluster ClJ1226.9+3332, recently discovered by us. At z=0.888 this
exceptional system is more X-ray luminous and more distant than both
MS1054.4-0321 and ClJ0152.7-1357, the previous record holders, thus
providing yet greater leverage for cosmological studies of cluster
evolution. ClJ1226.9+3332 differs markedly from all other currently known
distant clusters in that it exhibits little substructure and may even host
a cooling flow, suggesting that it could be the first cluster to be
discovered at high redshift that is virialized. We propose joint HST and
Chandra observations to investigate the dynamical state of this extreme
object. This project will 1) take advantage of HST's superb resolution at
optical wavelengths to accurately map the mass distribution within 1.9 h^-
1_ 50 Mpc via strong and weak gravitational lensing, and 2) use Chandra's
unprecedented resolution in the X-ray waveband to obtain independent
constraints on the gas and dark matter distribution in the cluster core,
including the suspected cooling flow region. As a bonus, the proposed
WFPC2 observations will allow us to test the results by van Dokkum et al.\
(1998, 1999) on the properties of cluster galaxies (specifically merger
rate and morphologies) at z~ 0.8 from their HST study of MS1054.4-0321.
================================================================================
PI: Mike Gladders
Proposal Title: A New High-z Galaxy Cluster with Extraordinary Lensed Arcs From
Multiple Sources
Approved Chandra Time (Ksecs): 15
Scientific Category: COSMOLOGY
Abstract
In the course of the Red-Sequence Cluster Survey (a 100 deg^2 optical
imaging survey), we have discovered a stunning new example of strong
lensing by a relatively high redshift (z~0.7) cluster. This lens system
has more bright arcs, with better cluster azimuthal coverage than examples
of lower z lenses previously imaged by HST (e.g., Abell 370, CL2244-0221),
and is the only known lens at z>0.6 with such significant lensing. At
least 4 separate arcs are detected in our initial survey data, at 3-4
different cluster-centric radii and hence likely corresponding to at least
3 different background sources at 3 different redshifts. Moreover, these
arcs are relatively bright (R_c~21.5-24.2) and hence redshifts should be
readily obtainable using 8m class telescopes. The proposed HST WFPC2
imaging, in conjunction with proposed VLT spectroscopy, offers an
unprecedented opportunity to measure the core mass distribution of a
cluster at such a high redshift. In combination with requested coordinated
Chandra X-ray imaging, this will enable a direct comparison of the dark
matter and baryonic components of the cluster, and enable a measure of
cosmology via sources at different z. Furthermore, the arcs are bright
enough to allow a detailed look at several high-z galaxies, via image
reconstruction of the unlensed sources (only possible with HST images) and
detailed spectroscopy.
================================================================================
PI: Joel Bregman Proposal Title: Ultraluminous X-Ray Sources and Intermediate Mass Black Holes Approved Chandra Time (Ksecs): 3 Scientific Category: GALAXIES & CLUSTERS Abstract Ultraluminous X-ray sources (ULX) are second only to AGNs in point-source luminosity yet they have no known optical counterparts. These extraordinary X-ray objects, which radiate at the Eddington luminosity of a 30-100 M _\odot object, are non-nuclear sources in normal disk galaxies. \ One explanation is that they are binary systems where the accreting black hole has a mass of 30-100 M_\odot , although this challenges stellar evolutionary models, which do not predict remnants larger than about 10 M _\odot . Another possibility is that ULXs are intermediate mass black holes (10^3-10^4 M_\odot ), acting as micro- quasars in galaxy disks and representing the link between stellar black holes (4-10 M_\odot ) and supermassive black holes (10^6-10^10 M_\odot ). We can distinguish between the models by identifying the optical counterparts of ULXs and measuring their colors. \ This would be a fundamental step in gaining an understanding of these enigmatic and possibly new astronomical objects.
===============================================================================
PI: S. R. Kulkarni Proposal Title: Gamma-ray burst progenitors: probing their environment Approved Chandra Time (Ksecs): 55 Scientific Category: GALAXIES & CLUSTERS Abstract Gamma-ray burst astronomy is a field maturing at a phenomenal rate. Only three years after the discovery of fading long-wavelength counterparts, we now have distance measurements for dozens of events, we have developed a detailed theoretical framework for understanding the X-ray -- radio afterglow lightcurves, and observational evidence now ties the progenitors of long GRBs (those studied to-date) to the collapse of massive stars. While progress has been rapid, three important new observational and theoretical discoveries, formulated over the last twelve months, allow us to address new and in many cases more sophisticated questions than could have been posed a year ago. These developments: the discovery of X-ray lines in GRB 991216; the observation that N_H as deduced from X-ray afterglow are one to two orders of magnitude larger than the dust extinction inferred from optical afterglow; and the growing realization that the afterglow emission may exhibit features of dust echoes, appear to offer unexpected and new diagnostics that will directly inform us about the progenitor, the circum-progenitor material and the immediate interstellar environs. These motivate us to propose an aggressive program for cycle 10. As one of the most actively evolving areas in astronomy today, we anticipate the contributions of HST to be part of the foundations of this new and important field.
================================================================================ PI: William Welsh Proposal Title: Flares, Magnetic Reconnections and Accretion Disk Viscosity Approved Chandra Time (Ksecs): 25 Scientific Category: HOT STARS Abstract Accretion disks are invoked to explain a host of astrophysical phenomena, from protostellar objects to AGN. And yet the mechanism allowing accretion disks to operate are completely unknown. This proposal seeks to observe the ``smoking gun'' signature of magnetically--driven viscosity in accretion disks. Magnetically--induced viscosity is a plausible and generally accepted hypothesis (for esthetic reasons), but it is completely untested. Determining the cause of accretion disk viscosity is of major significance to all accretion--disk powered systems (e.g. CVs, X--ray binaries, AGN and protostellar disks). These data will also firmly establish the importance of magnetic fields in accretion disks. Because of its known flaring properites, we will observe the accretion disk in EM Cyg simulataneously with STIS/FUV and CHANDRA. The simultaneous X-rays are absolutely necessary for the unambiguous detection of accretion disk magnetic reconnection flares.
================================================================================
PI: Raghvendra Sahai
Proposal Title: A YSO-like pulsed astrophysical jet and bipolar nebula in a
dying star: WFPC2/STIS study of He2-90
Approved Chandra Time (Ksecs): 10
Scientific Category: ISM AND CIRCUMSTELLAR MATTER
Abstract
We have discovered an extended, highly-collimated, bipolar jet in He2-90,
an object long classified as a planetary nebula (PN). The discovery images
(obtained with WFPC2/HST) show that the morphology of He2-90 does not look
like that of any known PN, but resembles that of a classical young stellar
object (YSO). This appears to be a unique object. We will determine the
speed of the jet (only slightly inclined to the sky plane) through proper
motion observations of the knots in the jet: a 2nd-epoch WFPC2 H-alphapha
image will be obtained for comparison with the Sep99 discovery image. It
is crucial to observe the velocity field of the flow at the highest
spatial-resolution, as close as possible to the origin of the jet in order
to constrain theories for how the jet is driven, and the nature of the
central object. We propose to do this by mapping the jet near the central
source using the long-slit, medium resolution mode of STIS. We also
propose supplemental observations: low resolution STIS spectra for
obtaining nebular diagnostics, coupled with narrow-band imaging with WFPC2
in emission lines such as NII, OI and OIII and continuum filters for
mapping excitation variations in the nebula and jet and the extinction in
the central dense dusty disk region. Coordinated Chandra X-ray
observations (with ACIS-I) will be made to check the association of an
EGRET >~mma-ray source which lies in the direction of He2-90.
================================================================================
Last modified: 12/02/10
