50 research outputs found
Astro2010: State of the Profession Position Paper: The Value of Observatory-Class Missions
The dramatic success of NASA鈥檚 astrophysics science program over the past 20 years has resulted from a series of assets in space ranging from Small Explorers to Observatory-Class
missions. NASA鈥檚 Observatory-Class missions, such as the Chandra X-ray Observatory (CXO), the Hubble Space Telescope (HST), and the Spitzer Space Telescope (SST), form the
cornerstone of this program by providing all researchers, regardless of institutional affiliation, a spectrum of science opportunities across programs large and small. These observatories stand out in their breadth of capabilities and consequent diversity of high impact science, their reach within the scientific community, and their proven ability to inspire the nation. Each mission was
designed to address specific scientific imperatives recognized by past Decadal Survey Committees, whether it was to refine the extragalactic distance scale, examine galaxies as they were in the distant past, determine the relationship between black holes and quasars, observe the
ultimate fate of stars in their death throes, or reveal heavily obscured regions of star-formation. These were ambitious goals, as are those envisioned for future Observatory-Class missions, such as the James Webb Space Telescope (JWST)
Unveiling the Galaxy Population at 1.3 < z < 4: the HUDF05 NICMOS Parallel Fields
Using the Hubble Ultra Deep Field Near Infrared Camera and Multi-Object Spectrometer (HUDF-NICMOS) UDF05 parallel fields, we cross-matched 301 out of 630 galaxies with the ACS filters V606 and z850, NICMOS filters J110 and H160, and Spitzer IRAC filters at 3.6, 4.5, 5.8 , and 8.0 (mu)m. We modeled the spectral energy distributions (SEDs) to estimate: photometric redshifts, dust extinction, stellar mass, bolometric luminosity, starburst age and metallicity. To validate the photometric redshifts, comparisons with 16 spectroscopic redshifts give 75% within Delta or approx. 1.3. Based on the robustness of the photometric redshifts, we analyze a subsample of the 301 galaxies at 1.3 < or = z < or = 2 (35 objects) and 3 < or = z < or = 4 (31 objects) and determine that L(BoI) and the star formation rate increase significantly from z approx. 1.5 to 4. The Balmer decrement is indicative of more evolved galaxies, and at high redshifts, they serve as records of some of the first galaxies. Therefore, the galaxies in this sample are great candidates for future surveys with the James Webb Space Telescope and Atacama Large Millimeter Array
A spectroscopic study of IRAS F10214+4724
The z=2.286 IRAS galaxy F10214+4724 remains one of the most luminous galaxies
in the Universe, despite its gravitational lens magnification. We present
optical and near-infrared spectra of F10214+4724, with clear evidence for three
distinct components: lines of width ~1000 km/s from a Seyfert-II nucleus; <~200
km/s lines which are likely to be associated with star formation; and a broad
~4000 km/s CIII] 1909ang emission line which is blue-shifted by ~1000 km/s with
respect to the Seyfert-II lines. Our study of the Seyfert-II component leads to
several new results, including: (i) From the double-peaked structure in the Ly
alpha line, and the lack of Ly beta, we argue that the Ly alpha photons have
emerged through a neutral column of N_H ~ 2.5 x 10^{25}/m^2, possibly located
within the AGN narrow-line region as argued in several high redshift
radiogalaxies. (ii) The resonant O VI 1032,1036ang doublet (previously
identified as Ly beta) is in an optically thick (1:1) ratio. At face value this
implies an an extreme density (n_e ~ 10^{17}/m^3) more typical of broad line
region clouds. However, we attribute this instead to the damping wings of Ly
beta from the resonant absorption. (iii) A tentative detection of HeII 1086
suggests little extinction in the rest-frame ultraviolet.Comment: Accepted for publication in MNRAS. Uses BoxedEPS (included
James Webb Space Telescope Optical Simulation Testbed I: Overview and First Results
The James Webb Space Telescope (JWST) Optical Simulation Testbed (JOST) is a
tabletop workbench to study aspects of wavefront sensing and control for a
segmented space telescope, including both commissioning and maintenance
activities. JOST is complementary to existing optomechanical testbeds for JWST
(e.g. the Ball Aerospace Testbed Telescope, TBT) given its compact scale and
flexibility, ease of use, and colocation at the JWST Science & Operations
Center. We have developed an optical design that reproduces the physics of
JWST's three-mirror anastigmat using three aspheric lenses; it provides similar
image quality as JWST (80% Strehl ratio) over a field equivalent to a NIRCam
module, but at HeNe wavelength. A segmented deformable mirror stands in for the
segmented primary mirror and allows control of the 18 segments in piston, tip,
and tilt, while the secondary can be controlled in tip, tilt and x, y, z
position. This will be sufficient to model many commissioning activities, to
investigate field dependence and multiple field point sensing & control, to
evaluate alternate sensing algorithms, and develop contingency plans. Testbed
data will also be usable for cross-checking of the WFS&C Software Subsystem,
and for staff training and development during JWST's five- to ten-year mission.Comment: Proceedings of the SPIE, 9143-150. 13 pages, 8 figure
Comparing Local Starbursts to High-Redshift Galaxies: A Search for Lyman-Break Analogs
We compare the restframe far-ultraviolet (FUV) morphologies of 8 nearby interacting and starburst galaxies (Arp 269, M 82, Mrk 08, NGC 0520, NGC 1068, NGC 3079, NGC 3310, NGC 7673) with 54 galaxies at z approx.1.5 and 46 galaxies at z approx.4 in the Great Observatories Origins Deep Survey (GOODS) images taken with the Advanced Camera for Surveys onboard the Hubble Space Telescope. We calculate the Gini coefficient (G), the second order moment of 20% of the brightest pixels (M20), and the S ersic index (n). We find that 20% (11/54) of z approx.1.5 and 37% (17/46) of z approx.4 galaxies are bulge-like, using G and M20. We also find approx.70% of the z approx.1.5 and z approx.4 galaxies have exponential disks with n > 0.8. The 2D profile combined with the nonparametric methods provides more detail, concerning the nature of disturbed systems, such as merger and post-merger types. We also provide qualitative descriptions of each galaxy system and at each redshift. We conclude that Mrk 08, NGC 3079, and NGC 7673 have similar morphologies as the starburst FUV restframe galaxies and Lyman-break galaxies at z approx.1.5 and 4, and determine that they are Lyman-break analogs
Exploring the NRO Opportunity for a Hubble-sized Wide-field Near-IR Space Telescope -- NEW WFIRST
We discuss scientific, technical and programmatic issues related to the use
of an NRO 2.4m telescope for the WFIRST initiative of the 2010 Decadal Survey.
We show that this implementation of WFIRST, which we call "NEW WFIRST," would
achieve the goals of the NWNH Decadal Survey for the WFIRST core programs of
Dark Energy and Microlensing Planet Finding, with the crucial benefit of deeper
and/or wider near-IR surveys for GO science and a potentially Hubble-like Guest
Observer program. NEW WFIRST could also include a coronagraphic imager for
direct detection of dust disks and planets around neighboring stars, a
high-priority science and technology precursor for future ambitious programs to
image Earth-like planets around neighboring stars.Comment: 76 pages, 26 figures -- associated with the Princeton "New Telescope
Meeting
Science drivers and requirements for an Advanced Technology Large Aperture Space Telescope (ATLAST): Implications for technology development and synergies with other future facilities
The Advanced Technology Large-Aperture Space Telescope (ATLAST) is a concept
for an 8-meter to 16-meter UVOIR space observatory for launch in the 2025-2030
era. ATLAST will allow astronomers to answer fundamental questions at the
forefront of modern astronphysics, including "Is there life elsewhere in the
Galaxy?" We present a range of science drivers that define the main performance
requirements for ATLAST (8 to 16 milliarcsec angular resolution, diffraction
limited imaging at 0.5 {\mu}m wavelength, minimum collecting area of 45 square
meters, high sensitivity to light wavelengths from 0.1 {\mu}m to 2.4 {\mu}m,
high stability in wavefront sensing and control). We will also discuss the
synergy between ATLAST and other anticipated future facilities (e.g., TMT,
EELT, ALMA) and the priorities for technology development that will enable the
construction for a cost that is comparable to current generation
observatory-class space missions.Comment: 12 pages, 4 figures, to appear in "Space Telescopes and
Instrumentation 2010: Optical, Infrared, and Millimeter Wave," edited by
Jacobus M. Oschmann Jr., Mark C. Clampin, Howard A. MacEwen, Proc. of SPIE,
Vol. 7731, 77312
The Advanced Technology Large Aperture Space Telescope (ATLAST): Science Drivers and Technology Developments
The Advanced Technology Large-Aperture Space Telescope (ATLAST) is a concept for an 8-meter to 16-meter UVOIR space observatory for launch in the 2025-2030 era. ATLAST will allow astronomers to answer fundamental questions at the forefront of modern astrophysics, including "Is there life elsewhere in the Galaxy?" We present a range of science drivers and the resulting performance requirements for ATLAST (8 to 16 milliarcsecond angular resolution, diffraction limited imaging at 0.5 m wavelength, minimum collecting area of 45 square meters, high sensitivity to light wavelengths from 0.1 m to 2.4 m, high stability in wavefront sensing and control). We also discuss the priorities for technology development needed to enable the construction of ATLAST for a cost that is comparable to current generation observatory-class space missions. Keywords: Advanced Technology Large-Aperture Space Telescope (ATLAST); ultraviolet/optical space telescopes; astrophysics; astrobiology; technology development
The Advanced Technology Large Aperture Space Telescope (ATLAST): Science Drivers, Technology Developments, and Synergies with Other Future Facilities
The Advanced Technology Large-Aperture Space Telescope (ATLAST) is a concept for an 8-meter to 16-meter UVOIR space observatory for launch in the 2025-2030 era. ATLAST will allow astronomers to answer fundamental questions at the forefront of modern astrophysics, including "Is there life elsewhere in the Galaxy?" We present a range of science drivers that define the main performance requirements for ATLAST (8 to 16 milliarcsec angular resolution, diffraction limited imaging at 0.5 m wavelength, minimum collecting area of 45 square meters, high sensitivity to light wavelengths from 0.1 m to 2.4 m, high stability in wavefront sensing and control). We will also discuss the synergy between ATLAST and other anticipated future facilities (e.g., TMT, EELT, ALMA) and the priorities for technology development that will enable the construction for a cost that is comparable to current generation observatory-class space missions