7 research outputs found
The infrared imaging spectrograph (IRIS) for TMT: electronics-cable architecture
The InfraRed Imaging Spectrograph (IRIS) is a first-light instrument for the
Thirty Meter Telescope (TMT). It combines a diffraction limited imager and an
integral field spectrograph. This paper focuses on the electrical system of
IRIS. With an instrument of the size and complexity of IRIS we face several
electrical challenges. Many of the major controllers must be located directly
on the cryostat to reduce cable lengths, and others require multiple bulkheads
and must pass through a large cable wrap. Cooling and vibration due to the
rotation of the instrument are also major challenges. We will present our
selection of cables and connectors for both room temperature and cryogenic
environments, packaging in the various cabinets and enclosures, and techniques
for complex bulkheads including for large detectors at the cryostat wall
The infrared imaging spectrograph (IRIS) for TMT: electronics-cable architecture
The InfraRed Imaging Spectrograph (IRIS) is a first-light instrument for the Thirty Meter Telescope (TMT). It combines a diffraction limited imager and an integral field spectrograph. This paper focuses on the electrical system of IRIS. With an instrument of the size and complexity of IRIS we face several electrical challenges. Many of the major controllers must be located directly on the cryostat to reduce cable lengths, and others require multiple bulkheads and must pass through a large cable wrap. Cooling and vibration due to the rotation of the instrument are also major challenges. We will present our selection of cables and connectors for both room temperature and cryogenic environments, packaging in the various cabinets and enclosures, and techniques for complex bulkheads including for large detectors at the cryostat wall
The infrared imaging spectrograph (IRIS) for TMT: electronics-cable architecture
The InfraRed Imaging Spectrograph (IRIS) is a first-light instrument for the Thirty Meter Telescope (TMT). It combines a diffraction limited imager and an integral field spectrograph. This paper focuses on the electrical system of IRIS. With an instrument of the size and complexity of IRIS we face several electrical challenges. Many of the major controllers must be located directly on the cryostat to reduce cable lengths, and others require multiple bulkheads and must pass through a large cable wrap. Cooling and vibration due to the rotation of the instrument are also major challenges. We will present our selection of cables and connectors for both room temperature and cryogenic environments, packaging in the various cabinets and enclosures, and techniques for complex bulkheads including for large detectors at the cryostat wall
Constraining the X-ray - Infrared spectral index of second-timescale flares from SGR1935+2154 with Palomar Gattini-IR
The Galactic magnetar SGR1935+2154 has been reported to produce the first
known example of a bright millisecond duration radio burst (FRB 200428) similar
to the cosmological population of fast radio bursts (FRBs), bolstering the
association of FRBs to active magnetars. The detection of a coincident bright
X-ray burst has revealed the first observed multi-wavelength counterpart of a
FRB. However, the search for similar emission at optical wavelengths has been
hampered by the high inferred extinction on the line of sight. Here, we present
results from the first search for second-timescale emission from the source at
near-infrared wavelengths using the Palomar Gattini-IR observing system in
J-band, made possible by a recently implemented detector read-out mode that
allowed for short exposure times of 0.84 s with 99.9% observing efficiency.
With a total observing time of 12 hours (47728 images) on source, we place
median limits on the second-timescale emission of mJy (13.1
AB mag). We present non-detection limits from epochs of four simultaneous X-ray
bursts detected by the Insight-{\it HXMT} and {\it NuSTAR} telescopes during
our observing campaign. The limits translate to an extinction corrected fluence
limit of Jy ms for an estimated extinction of mag. These
limits provide the most stringent constraints to date on the fluence of flares
at frequencies of Hz, and constrain the ratio of the
near-infrared (NIR) fluence to that of coincident X-ray bursts to . Our observations were sensitive enough to easily detect
a near-infrared counterpart of FRB 200428 if the NIR emission falls on the same
power law as that observed across its radio to X-ray spectrum. The
non-detection of NIR emission around the coincident X-ray bursts constrains the
fluence index of the brightest burst to be steeper than .Comment: 10 pages, 4 figures, submitted to ApJL. Comments welcom
Palomar Gattini-IR: Survey overview, data processing system, on-sky performance and first results
Palomar Gattini-IR is a new wide-field, near-infrared (NIR) robotic time domain survey operating at Palomar Observatory. Using a 30 cm telescope mounted with a H2RG detector, Gattini-IR achieves a field of view (FOV) of 25 sq. deg. with a pixel scale of 8.β7 in J-band. Here, we describe the system design, survey operations, data processing system and on-sky performance of Palomar Gattini-IR. As a part of the nominal survey, Gattini-IR scans β7500 square degrees of the sky every night to a median 5Ο depth of 15.7 AB mag outside the Galactic plane. The survey covers β15,000 square degrees of the sky visible from Palomar with a median cadence of 2 days. A real-time data processing system produces stacked science images from dithered raw images taken on sky, together with point-spread function (PSF)-fit source catalogs and transient candidates identified from subtractions within a median delay of β4 hr from the time of observation. The calibrated data products achieve an astrometric accuracy (rms) of β0.β7 with respect to Gaia DR2 for sources with signal-to-noise ratio > 10, and better than β0.β35 for sources brighter than β12 Vega mag. The photometric accuracy (rms) achieved in the PSF-fit source catalogs is better than β3% for sources brighter than β12 Vega mag and fainter than the saturation magnitude of β8.5 Vega mag, as calibrated against the Two Micron All Sky Survey catalog. The detection efficiency of transient candidates injected into the images is better than 90% for sources brighter than the 5Ο limiting magnitude. The photometric recovery precision of injected sources is 3% for sources brighter than 13 mag, and the astrometric recovery rms is β0.β9. Reference images generated by stacking several field visits achieve depths of β³16.5 AB mag over 60% of the sky, while it is limited by confusion in the Galactic plane. With a FOV β40Γ larger than any other existing NIR imaging instrument, Gattini-IR is probing the reddest and dustiest transients in the local universe such as dust obscured supernovae in nearby galaxies, novae behind large columns of extinction within the galaxy, reddened microlensing events in the Galactic plane and variability from cool and dust obscured stars. We present results from transients and variables identified since the start of the commissioning period