The Faint Intergalactic Redshifted Emission Balloon (FIREBALL) had its first scientific flight in June 2009.
The instrument combines microchannel plate detector technology with fiber-fed integral field spectroscopy on an
unstable stratospheric balloon gondola platform. This unique combination poses a series of calibration and data
reduction challenges that must be addressed and resolved to allow for accurate data analysis. We discuss our
approach and some of the methods we are employing to accomplish this task.
The Faint Intergalactic Redshifted Emission Balloon (FIREBALL) had its first scientific flight in June 2009.
The instrument is a 1 meter class balloon-borne telescope equipped with a vacuum-ultraviolet integral field
spectrograph intended to detect emission from the inter-galactic medium at redshifts 0.3 < z < 1.0. The
scientific goals and the challenging environment place strict constraints on the pointing and tracking systems of
the gondola. In this manuscript we briefly review our pointing requirements, discuss the methods and solutions
used to meet those requirements, and present the aspect reconstruction results from the first successful scientific
flight.
FIREBall (the Faint Intergalactic Redshifted Emission Balloon) is a balloon-borne 1m telescope coupled to an
ultraviolet fiber-fed spectrograph. FIREBall is designed to study the faint and diffuse emission of the warm hot
intergalactic medium, until now detected primarily in absorption. FIREBall is a pathfinding mission to test new
technology and make new constraints on the temperature and density of this gas. FIREBall has flown twice,
the most recent flight (June 2009) a fully functioning science flight. Here we describe the spectrograph design,
current setup, and calibration measurements from the campaign.
FIREBALL (the Faint Intergalactic Redshifted Emission Balloon) is a balloon-borne 1m telescope coupled to an
ultraviolet fiber-fed spectrograph. FIREBALL is designed to study the faint and diffuse emission of the intergalactic
medium, until now detected primarily in absorption. FIREBALL is a path finding mission to test new technology
and make new constraints on the temperature and density of this gas. We report on the first successful science flight
of FIREBALL, in June 2009, which proved every aspect of the complex instrument performance, and provided the
strongest measurements and constraints on IGM emission available from any instrument.
We are designing the Keck Cosmic Web Imager (KCWI) as a new facility instrument for the Keck II telescope at the
W. M. Keck Observatory (WMKO). KCWI is based on the Cosmic Web Imager (CWI), an instrument that has recently
had first light at the Hale Telescope. KCWI is a wide-field integral-field spectrograph (IFS) optimized for precision sky
limited spectroscopy of low surface brightness phenomena. KCWI will feature high throughput, and flexibility in field of
view (FOV), spatial sampling, bandpass, and spectral resolution. KCWI will provide full wavelength coverage (0.35 to
1.05 μm) using optimized blue and red channels. KCWI will provide a unique and complementary capability at WMKO
(optical band integral field spectroscopy) that is directly connected to one of the Observatory's strategic goals (faint
object, high precision spectroscopy), at a modest cost and on a competitive time scale, made possible by its simple
concept and the prior demonstration of CWI.
We describe the Cosmic Web Imager (CWI), a UV-VIS integral eld spectrograph designed for the Hale 200"
telescope at the Palomar Observatory. CWI has been built specically for the observation of diuse radiation.
The instrument eld of view is 60"40" with spectral resolving power of R5000 and seeing limited spatial
resolution. It utilizes volume phase holographic gratings and is intended to cover the spectral range 3800A to
9500A with an instantaneous bandwidth of 450A. CWI saw rst light in July 2009, and conducted its rst
successful scientic observations in May 2010.
FIREBall (Faint Intergalactic Redshifted Emission Balloon) had a successful first engineering flight in July of 2007 from
Palestine, Texas. Here we detail the design and construction of the spectrograph. FIREBall consists of a 1m telescope
coupled to a fiber-fed ultraviolet spectrograph flown on a short duration balloon. The spectrograph is designed to map
hydrogen and metal line emission from the intergalactic medium at several redshifts below z=1, exploiting a small
window in atmospheric oxygen absorption at balloon altitudes. The instrument is a wide-field IFU fed by almost 400
fibers. The Offner mount spectrograph is designed to be sensitive in the 195-215nm window accessible at our altitudes
of 35-40km. We are able to observe Lyα, as well as OVI and CIV doublets, from 0.3 < z < 0.9. Observations of UV
bright B stars and background measurements allow characterization of throughput for the entire system and will inform
future flights.
We are developing the Cosmic Web Imager (CWI) to detect and map emission from the intergalactic medium (IGM).
CWI will observe the strong, redshift UV resonance lines of Lyα 1216, CIV 1550, and OVI 1033 over 3600-9000 Å to
trace IGM at 1 < z < 7. CWI is an integral-field spectrograph designed for the Hale Telescope at Palomar Observatory.
CWI combines in a novel way three mature and extensively used instrumental techniques. The Integral Field Unit (IFU)
provides a wide 2D field of view of 60 × 40 arcsec2 for observing extended emission over a large region. The
spectrograph using Volume-Phase Holographic gratings have high peak diffraction efficiency and are tunable for
covering a large bandpass with a single grating. A low read noise CCD combined with source/background shiftand-nod
allowing control of systematics and Poisson-imited sky subtraction to observe the low surface brightness universe. With
a resolution of R=10,000 CWI is sensitive to limiting surface brightness ranging from 25 - 27.5 mag/arcsec2 (10 min - 8
hours integration). Recent high resolution simulations predict Lyα Fluorescence from IGM at 100 - 1000 LU1. CWI with
sensitivity of ~200 LU improves the current observational effort by an order of magnitude and enables us to explore
wide range of overdensity (δ ~ 30 - 104) testing the standard model of structure formation in the universe. CWI also
serves as the counter part to the balloon borne integral-field spectrograph Faint Intergalactic medium Redshifted
Emission Balloon (FIREBALL) currently being built and planned to be launched in Summer 2007. FIREBALL will
observe Lyα Fluorescence from IGM at z = 0.7. CWI combined with FIREBALL will enable us to observe the evolution
of IGM and the low surface brightness universe.
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