The infrared imaging spectrograph (IRIS) for TMT: sensitivities and simulations

We present sensitivity estimates for point and resolved astronomical sources for the current design of the InfraRed Imaging Spectrograph (IRIS) on the future Thirty Meter Telescope (TMT). IRIS, with TMT's adaptive optics system, will achieve unprecedented point source sensitivities in the near-infrared (0.84 - 2.45 {\mu}m) when compared to systems on current 8-10m ground based telescopes. The IRIS imager, in 5 hours of total integration, will be able to perform a few percent photometry on 26 - 29 magnitude (AB) point sources in the near-infrared broadband filters (Z, Y, J, H, K). The integral field spectrograph, with a range of scales and filters, will achieve good signal-to-noise on 22 - 26 magnitude (AB) point sources with a spectral resolution of R=4,000 in 5 hours of total integration time. We also present simulated 3D IRIS data of resolved high-redshift star forming galaxies (1 < z < 5), illustrating the extraordinary potential of this instrument to probe the dynamics, assembly, and chemical abundances of galaxies in the early universe. With its finest spatial scales, IRIS will be able to study luminous, massive, high-redshift star forming galaxies (star formation rates ~ 10 - 100 M yr-1) at ~100 pc resolution. Utilizing the coarsest spatial scales, IRIS will be able to observe fainter, less massive high-redshift galaxies, with integrated star formation rates less than 1 M yr-1, yielding a factor of 3 to 10 gain in sensitivity compared to current integral field spectrographs. The combination of both fine and coarse spatial scales with the diffraction-limit of the TMT will significantly advance our understanding of early galaxy formation processes and their subsequent evolution into presentday galaxies.Comment: SPIE Astronomical Instrumentation 201

The InfraRed Imaging Spectrograph (IRIS) for TMT: latest science cases and simulations

The Thirty Meter Telescope (TMT) first light instrument IRIS (Infrared Imaging Spectrograph) will complete its preliminary design phase in 2016. The IRIS instrument design includes a near-infrared (0.85 - 2.4 micron) integral field spectrograph (IFS) and imager that are able to conduct simultaneous diffraction-limited observations behind the advanced adaptive optics system NFIRAOS. The IRIS science cases have continued to be developed and new science studies have been investigated to aid in technical performance and design requirements. In this development phase, the IRIS science team has paid particular attention to the selection of filters, gratings, sensitivities of the entire system, and science cases that will benefit from the parallel mode of the IFS and imaging camera. We present new science cases for IRIS using the latest end-to-end data simulator on the following topics: Solar System bodies, the Galactic center, active galactic nuclei (AGN), and distant gravitationally-lensed galaxies. We then briefly discuss the necessity of an advanced data management system and data reduction pipeline

The Infrared Imaging Spectrograph (IRIS) for TMT: Volume phase holographic grating performance testing and discussion

Maximizing the grating efficiency is a key goal for the first light instrument IRIS (Infrared Imaging Spectrograph) currently being designed to sample the diffraction limit of the TMT (Thirty Meter Telescope). Volume Phase Holographic (VPH) gratings have been shown to offer extremely high efficiencies that approach 100% for high line frequencies (i.e., 600 to 6000l/mm), which has been applicable for astronomical optical spectrographs. However, VPH gratings have been less exploited in the near-infrared, particularly for gratings that have lower line frequencies. Given their potential to offer high throughputs and low scattered light, VPH gratings are being explored for IRIS as a potential dispersing element in the spectrograph. Our team has procured near-infrared gratings from two separate vendors. We have two gratings with the specifications needed for IRIS current design: 1.51-1.82{\mu}m (H-band) to produce a spectral resolution of 4000 and 1.19- 1.37 {\mu}m (J-band) to produce a spectral resolution of 8000. The center wavelengths for each grating are 1.629{\mu}m and 1.27{\mu}m, and the groove densities are 177l/mm and 440l/mm for H-band R=4000 and J-band R=8000, respectively. We directly measure the efficiencies in the lab and find that the peak efficiencies of these two types of gratings are quite good with a peak efficiency of ~88% at the Bragg angle in both TM and TE modes at H-band, and 90.23% in TM mode, 79.91% in TE mode at J-band for the best vendor. We determine the drop in efficiency off the Bragg angle, with a 20-23% decrease in efficiency at H-band when 2.5 degree deviation from the Bragg angle, and 25%-28% decrease at J-band when 5{\deg} deviation from the Bragg angle.Comment: Proceedings of the SPIE, 9147-33

Geographic Distribution Records for Scolopendromorph Centipedes (Arthropoda: Chilopoda) from Arkansas, Oklahoma, and Texas

During 2001-2003, we collected eight species of scolopendromorph centipedes from 17 counties of Arkansas (AR), seven counties of Oklahoma (OK), and 17 counties of Texas (TX). The following taxa were collected: Cryptops leucopodus (Rafinesque) from Bowie and Cass counties, TX, and Pulaski County, AR; Hemiscolopendra marginata (Say) from Columbia, Garland, Hempstead, Little River, Pike, Polk, and Yell counties, AR, and Cass, Cherokee, Coryell, Houston, Johnson, Kimble, Marion, Nacogdoches, Smith, and Tom Green counties, TX; Scolopocryptops rubiginosus L. Koch from Bowie and Dallas counties, TX; Scolopocryptops sexspinosus (Say) from Clark, Columbia, Conway, Faulkner, Hot Spring, Garland, Miller, Montgomery, Polk, Pope, and Pulaski counties, AR, LeFlore and McCurtain counties, OK, and Marion, Red River, and Rusk counties, TX; Scolopendra hews Girard from Atoka, Major, and McCurtain counties, OK; Scolopendra polymorpha Wood from Woodward County, OK; Theatops posticus (Say) from Montgomery County, AR, Choctaw, Marshall, and McCurtain counties, OK, and Cass, Dallas, Freestone, Hopkins, Houston, Red River, and Titus counties, TX; and Theatops spinicaudus (Wood) from Garland, Hot Spring, Little River, Pike, and Scott counties, AR, and Atoka, Choctaw, and McCurtain counties, OK. Most significantly, our records of S. rubiginosus are well outside its distributional range as depicted in Shelley (2002). A total of 43 new county records is documented, including 14 in Arkansas, nine in Oklahoma, and 20 in Texas

Millipeds (Arthropoda: Diplopoda) of the Ark-La-Tex. II. Distributional Records for Some Species of Western and Central Arkansas and Easter and Southeastern Oklahoma

We collected millipeds between November 2001 and March 2002 at several sites in the Ouachita Provinces of western (Garland, Hot Spring, Pike, and Polk counties) and central Arkansas (Pulaski County) and the Ouachita and Kiamichi Provinces of southeastern Oklahoma (LeFlore and McCurtain counties). The following millipeds were found: Eurymerodesmus dubius, Auturus louisianus louisianus, Pseudopolydesmus pinetorum, and Cambala minor in Garland County; Eurymerodesmus sp., A. I. louisianus, P. pinetorum, and juveniles of the family Parajulidae (tribe Aniulini) from Hot Spring County; E. dubius, A. I. louisianus, and juveniles of the family Cleidogonidae from Pike County; Brachycybe lecontei, A. I. louisianus, Abacion tesselatum, and P. pinetorum in Polk County; Eurymerodesmus pulaski, P. pinetorum, Auturus evides, C. minor, B. lecontei, and a possible new species of Cleidogona in Pulaski County; A. I. louisianus, Apheloria virginiensis ?reducta, P. pinetorum, Narceus americanus, and E. dubius in McCurtain County; and B. lecontei, A.l. louisianus, Eurymerodesmus b. birdi, A. Ptesselatum, and juveniles of the family Parajulidae (tribe Aniulini) in LeFlore County. Two new state records are documented for Oklahoma: B. lecontei (Platydesmida: Andrognathidae), a record not only for the genus and species but also for the family and order; and E. dubius, the westernmost locality ever reported for the species

Millipeds (Arthropoda: Diplopoda) of the Ark-La-Tex. III. Additional Records from Arkansas

As part of an on-going effort by the second author (RMS) to elucidate the North American diplopod fauna, we collected millipeds in 14 Arkansas counties between April 2002 and October 2003. Additional information for these species is recorded from the holdings at the University of Arkansas Arthropod Museum along with unpublished records from other institutions in the second author\u27s files. The following species were identified: Abacion tesselatum, A. texense, Aliulus caddoensis, Apheloria virginiensis ?reducta, Auturus evides, A. louisianus louisianus, Brachycybe lecontei, Brachyiulus lusitanus, B.pusillus, Cambala minor, Desmonus pudicus, Eurymerodesmus birdibirdi, E. polkensis, E. pulaski, E. serratus, Narceus americanus, Oriulus venustus, Oxidis gracilis, Pseudopolydesmus pinetorum, P. serratus, and Virgoiulus minutus. A different and potentially new species of Pseudopolydesmus was collected in the entrance to Searcy Cave, Independence County. Three new state and 68 new county records are documented

The InfraRed Imaging Spectrograph (IRIS) for TMT: Reflective ruled diffraction grating performance testing and discussion

We present the efficiency of near-infrared reflective ruled diffraction gratings designed for the InfraRed Imaging Spectrograph (IRIS). IRIS is a first light, integral field spectrograph and imager for the Thirty Meter Telescope (TMT) and narrow field infrared adaptive optics system (NFIRAOS). We present our experimental setup and analysis of the efficiency of selected reflective diffraction gratings. These measurements are used as a comparison sample against selected candidate Volume Phase Holographic (VPH) gratings (see Chen et al., this conference). We investigate the efficiencies of five ruled gratings designed for IRIS from two separate vendors. Three of the gratings accept a bandpass of 1.19-1.37 {\mu}m (J band) with ideal spectral resolutions of R=4000 and R=8000, groove densities of 249 and 516 lines/mm, and blaze angles of 9.86 and 20.54 degrees, respectively. The other two gratings accept a bandpass of 1.51-1.82 {\mu}m (H Band) with an ideal spectral resolution of R=4000, groove density of 141 lines/mm, and blaze angle of 9.86{\deg}. We measure the efficiencies off blaze angle for all gratings and the efficiencies between the polarization transverse magnetic (TM) and transverse electric (TE) states. The peak reflective efficiencies are 98.90 +/- 3.36% (TM) and 84.99 +/- 2.74% (TM) for the H-band R=4000 and J-band R=4000 respectively. The peak reflective efficiency for the J-band R=8000 grating is 78.78 +/- 2.54% (TE). We find that these ruled gratings do not exhibit a wide dependency on incident angle within +/-3{\deg}. Our best-manufactured gratings were found to exhibit a dependency on the polarization state of the incident beam with a ~10-20% deviation, consistent with the theoretical efficiency predictions.Comment: Proceedings of the SPIE, 9147-34