85 research outputs found
The Future of Direct Supermassive Black Hole Mass Estimates
(Abridged) The repeated discovery of supermassive black holes (SMBHs) at the
centers of galactic bulges, and the discovery of relations between the SMBH
mass (M) and the properties of these bulges, has been fundamental in directing
our understanding of both galaxy and SMBH formation and evolution. However,
there are still many questions surrounding the SMBH - galaxy relations. For
example, are the scaling relations linear and constant throughout cosmic
history, and do all SMBHs lie on the scaling relations? These questions can
only be answered by further high quality direct M estimates from a wide range
in redshift. In this paper we determine the observational requirements
necessary to directly determine SMBH masses, across cosmological distances,
using current M modeling techniques. We also discuss the SMBH detection
abilities of future facilities. We find that if different M modeling
techniques, using different spectral features, can be shown to be consistent,
then both 30 m ground- and 16 m space-based telescopes will be able to sample M
1e9Msol across ~95% of cosmic history. However, we find that the abilities of
ground-based telescopes critically depend on future advancements in adaptive
optics systems; more limited AO systems will result in limited effective
spatial resolutions, and forces observations towards the near-infrared where
spectral features are weaker and more susceptible to sky features. Ground-based
AO systems will always be constrained by relatively bright sky backgrounds and
atmospheric transmission. The latter forces the use of multiple spectral
features and dramatically impacts the SMBH detection efficiency. The most
efficient way to advance our database of direct SMBH masses is therefore
through the use of a large (16 m) space-based UVOIR telescope.Comment: PASP Accepte
High Accuracy Near-infrared Imaging Polarimetry with NICMOS
The findings of a nine orbit calibration plan carried out during HST Cycle
15, to fully determine the NICMOS camera 2 (2.0 micron) polarization
calibration to high accuracy, are reported. Recently Ueta et al. and Batcheldor
et al. have suggested that NICMOS possesses a residual instrumental
polarization at a level of 1.2-1.5%. This would completely inhibit the data
reduction in a number of GO programs, and hamper the ability of the instrument
to perform high accuracy polarimetry. We obtained polarimetric calibration
observations of three polarimetric standards at three spacecraft roll angles
separated by ~60deg. Combined with archival data, these observations were used
to characterize the residual instrumental polarization in order for NICMOS to
reach its full potential of accurate imaging polarimetry at p~1%. Using these
data, we place an 0.6% upper limit on the instrumental polarization and
calculate values of the parallel transmission coefficients that reproduce the
ground-based results for the polarimetric standards. The uncertainties
associated with the parallel transmission coefficients, a result of the
photometric repeatability of the observations, are seen to dominate the
accuracy of p and theta. However, the updated coefficients do allow imaging
polarimetry of targets with p~1.0% at an accuracy of +/-0.6% and +/-15deg. This
work enables a new caliber of science with HST.Comment: 13 pages, 9 figures, PASP accepte
High Accuracy Imaging Polarimetry with NICMOS
The ability of NICMOS to perform high accuracy polarimetry is currently
hampered by an uncalibrated residual instrumental polarization at a level of
1.2-1.5%. To better quantify and characterize this residual we obtained
observations of three polarimetric standard stars at three separate space-craft
roll angles. Combined with archival data, these observations were used to
characterize the residual instrumental polarization to enable NICMOS to reach
its full polarimetric potential. Using these data, we calculate values of the
parallel transmission coefficients that reproduce the ground-based results for
the polarimetric standards. The uncertainties associated with the parallel
transmission coefficients, a result of the photometric repeatability of the
observations, dominate the accuracy of p and theta. However, the new
coefficients now enable imaging polarimetry of targets with p~1.0% at an
accuracy of +/-0.6% and +/-15 degrees.Comment: 5 pages, 2 figures. Contributed talk, "Astronomical Polarimetry 2008.
Science from Small to Large Telescopes" La Malbaie, Quebec, Canada, 200
Constraints on Jupiters from Observations of Galactic bulge microlensing events during 2000
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