The Infrared Array Camera (IRAC) was an infrared camera system on the Spitzer Space Telescope which operated in the mid-infrared spectrum.[1] It was composed of four detectors that operated simultaneously at different wavelengths; all four were in use until 2009 May 15 when the Spitzercryostat ran out of liquid helium.[2] After then, the spacecraft operated in a warm extended mission, in which two of the four detectors remained functional, until the Spitzer mission was terminated on 2020 January 30.[2]
Infrared observations can see objects hidden in visible light, such as HUDF-JD2 shown. This shows how the Spitzer IRAC camera was able see beyond the wavelengths of Hubble's instrumentsFour-band IRAC image of the Trifid Nebula. The wavelengths the camera sees are mapped to the visible spectrum for a false color image that humans can see. Here, the mapping is blue for 3.6 μm, green for 4.5 μm, orange for 5.8 μm, and red for 8.0 μm.IRAC filters
During its primary mission, IRAC was able to simultaneously operate in four wavelengths: 3.6 μm, 4.5 μm, 5.8 μm, and 8.0 μm.[1][3] Each infrared detector had dimensions of 256×256 pixels—a significant improvement over previous spaceborne infrared telescopes—and each image taken covered 5.12 square arcminutes of sky with each pixel covering 1.2 arcseconds.[1][4] The detectors operating at 3.6 μm and 4.5 μm were constructed with indium antimonide (InSb), while the 5.8 μm and 8.0 μm detectors were made of silicondoped with arsenic (Si:As).[1][3][5] The telescope's primary and secondary mirrors, along with its supporting structure, were made mostly of beryllium.[4] The telescope was cryogenically cooled to around 2 K (−271 °C; −456 °F); the 3.6 μm and 4.5 μm detectors operated at 15 K (−258 °C; −433 °F) and the 5.8 μm and 8.0 μm detectors operated at 6 K (−267 °C; −449 °F).[6]
After Spitzer's liquid helium coolant ran out on 2009 May 15, the spacecraft warmed up over several months.[7] IRAC stabilized at its warm mission operating temperature of 28.7 K (−244 °C; −408 °F) on 2009 September 18.[7] This meant that the 5.8 μm and 8.0 μm detectors could not function as they required the cryogenic cooling,[1] but the 3.6 μm and 4.5 μm detectors remained about as sensitive as they were during the primary mission.[8] The other two Spitzer instruments (IRS and MIPS) likewise ceased to function as they worked at longer wavelengths, leaving IRAC as the sole operational instrument.[8]
The cryogenic assembly of IRAC is contained in the Multiple Instrument Chamber (MIC), which also houses the other focal plane elements and the pointing calibration reference sensor. In the MIC is the Infrared Array Camera, Infrared Spectrograph, and Multiband Imaging Photometer, as well as the pointing calibration reference sensor.[9] The MIC is attached to the cryostat and was intended to keep the science instruments, including IRAC, cold but also functioned to keep out stray light.[9] The MIC is mounted to the helium chamber inside the cryostat vacuum shell, not only to efficiently keep the instruments cold but to seal out any stray light.[9] The IRAC warm electronics assembly is housed in the spacecraft bus.[6] The IRAC instrument was built by the Goddard Space Flight Center and the detectors were built by Raytheon. Its operational and scientific management is handled by the Smithsonian Astrophysical Observatory.[6]
IRAC was capable of observing in the wavelengths of 3.6, 4.5, 5.8, and 8.0 microns. When its coolant ran out, only the two shorter wavelengths remained usable.[1][3]
^ abcdef. Spitzer Space Telescope. NASA / JPL / Caltech. Archived from the original on 13 June 2010. Retrieved 13 January 2017.
^ abSzondy, David (28 August 2016). "Spitzer goes "Beyond" for final mission". New Atlas. Retrieved 13 January 2017.
^ abcFazio, G. G.; Hora, J. L.; Allen, L. E.; Ashby, M. L. N.; Barmby, P.; et al. (September 2004). "The Infrared Array Camera (IRAC) for the Spitzer Space Telescope". The Astrophysical Journal Supplement Series. 154 (1): 10–17. arXiv:astro-ph/0405616. Bibcode:2004ApJS..154...10F. doi:10.1086/422843. S2CID 119344105.
^ ab. Spitzer Space Telescope. NASA / JPL / Caltech. Archived from the original on 13 March 2014. Retrieved 13 January 2017.
^"IRAC Instrument Handbook: Appendix E. Acronyms". NASA/IPAC Infrared Science Archive. Spitzer Documentation and Tools. NASA / JPL / Caltech. Retrieved 13 January 2017.
^ abcGehrz, R. D.; Roellig, T. L.; Werner, M. W.; Fazio, G. G.; Houck, J. R.; et al. (January 2007). "The NASA Spitzer Space Telescope" (PDF). Review of Scientific Instruments. 78 (1). 011302. Bibcode:2007RScI...78a1302G. doi:10.1063/1.2431313. PMID 17503900.
^ ab"Warm IRAC Image Characteristics". NASA/IPAC Infrared Science Archive. Spitzer Documentation and Tools. NASA / JPL / Caltech. Retrieved 13 January 2017.
^ abHora, Joseph L.; Marengo, Massimo; Park, Rebecca; Wood, Denise; Hoffmann, William F.; et al. (September 2012). Clampin, Mark C; Fazio, Giovanni G; MacEwen, Howard A; Oschmann, Jacobus M (eds.). "The IRAC point response function in the warm Spitzer mission" (PDF). Proceedings of the SPIE. Space Telescopes and Instrumentation 2012: Optical, Infrared, and Millimeter Wave. Space Telescopes and Instrumentation 2012: Optical, Infrared, and Millimeter Wave. 8442. 844239. Bibcode:2012SPIE.8442E..39H. doi:10.1117/12.926894. S2CID 120825801.
^ abc. Spitzer Space Telescope. NASA / JPL / Caltech. Archived from the original on 13 March 2014. Retrieved 13 January 2017.
infrared, array, camera, irac, infrared, camera, system, spitzer, space, telescope, which, operated, infrared, spectrum, composed, four, detectors, that, operated, simultaneously, different, wavelengths, four, were, until, 2009, when, spitzer, cryostat, liquid. The Infrared Array Camera IRAC was an infrared camera system on the Spitzer Space Telescope which operated in the mid infrared spectrum 1 It was composed of four detectors that operated simultaneously at different wavelengths all four were in use until 2009 May 15 when the Spitzer cryostat ran out of liquid helium 2 After then the spacecraft operated in a warm extended mission in which two of the four detectors remained functional until the Spitzer mission was terminated on 2020 January 30 2 Infrared observations can see objects hidden in visible light such as HUDF JD2 shown This shows how the Spitzer IRAC camera was able see beyond the wavelengths of Hubble s instruments Four band IRAC image of the Trifid Nebula The wavelengths the camera sees are mapped to the visible spectrum for a false color image that humans can see Here the mapping is blue for 3 6 mm green for 4 5 mm orange for 5 8 mm and red for 8 0 mm IRAC filters During its primary mission IRAC was able to simultaneously operate in four wavelengths 3 6 mm 4 5 mm 5 8 mm and 8 0 mm 1 3 Each infrared detector had dimensions of 256 256 pixels a significant improvement over previous spaceborne infrared telescopes and each image taken covered 5 12 square arcminutes of sky with each pixel covering 1 2 arcseconds 1 4 The detectors operating at 3 6 mm and 4 5 mm were constructed with indium antimonide InSb while the 5 8 mm and 8 0 mm detectors were made of silicon doped with arsenic Si As 1 3 5 The telescope s primary and secondary mirrors along with its supporting structure were made mostly of beryllium 4 The telescope was cryogenically cooled to around 2 K 271 C 456 F the 3 6 mm and 4 5 mm detectors operated at 15 K 258 C 433 F and the 5 8 mm and 8 0 mm detectors operated at 6 K 267 C 449 F 6 After Spitzer s liquid helium coolant ran out on 2009 May 15 the spacecraft warmed up over several months 7 IRAC stabilized at its warm mission operating temperature of 28 7 K 244 C 408 F on 2009 September 18 7 This meant that the 5 8 mm and 8 0 mm detectors could not function as they required the cryogenic cooling 1 but the 3 6 mm and 4 5 mm detectors remained about as sensitive as they were during the primary mission 8 The other two Spitzer instruments IRS and MIPS likewise ceased to function as they worked at longer wavelengths leaving IRAC as the sole operational instrument 8 The cryogenic assembly of IRAC is contained in the Multiple Instrument Chamber MIC which also houses the other focal plane elements and the pointing calibration reference sensor In the MIC is the Infrared Array Camera Infrared Spectrograph and Multiband Imaging Photometer as well as the pointing calibration reference sensor 9 The MIC is attached to the cryostat and was intended to keep the science instruments including IRAC cold but also functioned to keep out stray light 9 The MIC is mounted to the helium chamber inside the cryostat vacuum shell not only to efficiently keep the instruments cold but to seal out any stray light 9 The IRAC warm electronics assembly is housed in the spacecraft bus 6 The IRAC instrument was built by the Goddard Space Flight Center and the detectors were built by Raytheon Its operational and scientific management is handled by the Smithsonian Astrophysical Observatory 6 Contents 1 Bands summary 2 See also 3 References 4 External linksBands summary editIRAC was capable of observing in the wavelengths of 3 6 4 5 5 8 and 8 0 microns When its coolant ran out only the two shorter wavelengths remained usable 1 3 See also editMIRI Mid Infrared Instrument NIRCam a James Webb Space Telescope instrument for 0 6 to 5 mm lightReferences edit a b c d e f The Infrared Array Camera IRAC Spitzer Space Telescope NASA JPL Caltech Archived from the original on 13 June 2010 Retrieved 13 January 2017 a b Szondy David 28 August 2016 Spitzer goes Beyond for final mission New Atlas Retrieved 13 January 2017 a b c Fazio G G Hora J L Allen L E Ashby M L N Barmby P et al September 2004 The Infrared Array Camera IRAC for the Spitzer Space Telescope The Astrophysical Journal Supplement Series 154 1 10 17 arXiv astro ph 0405616 Bibcode 2004ApJS 154 10F doi 10 1086 422843 S2CID 119344105 a b Infrared Detector Developments Spitzer Space Telescope NASA JPL Caltech Archived from the original on 13 March 2014 Retrieved 13 January 2017 IRAC Instrument Handbook Appendix E Acronyms NASA IPAC Infrared Science Archive Spitzer Documentation and Tools NASA JPL Caltech Retrieved 13 January 2017 a b c Gehrz R D Roellig T L Werner M W Fazio G G Houck J R et al January 2007 The NASA Spitzer Space Telescope PDF Review of Scientific Instruments 78 1 011302 Bibcode 2007RScI 78a1302G doi 10 1063 1 2431313 PMID 17503900 a b Warm IRAC Image Characteristics NASA IPAC Infrared Science Archive Spitzer Documentation and Tools NASA JPL Caltech Retrieved 13 January 2017 a b Hora Joseph L Marengo Massimo Park Rebecca Wood Denise Hoffmann William F et al September 2012 Clampin Mark C Fazio Giovanni G MacEwen Howard A Oschmann Jacobus M eds The IRAC point response function in the warm Spitzer mission PDF Proceedings of the SPIE Space Telescopes and Instrumentation 2012 Optical Infrared and Millimeter Wave Space Telescopes and Instrumentation 2012 Optical Infrared and Millimeter Wave 8442 844239 Bibcode 2012SPIE 8442E 39H doi 10 1117 12 926894 S2CID 120825801 a b c The Multiple Instrument Chamber Spitzer Space Telescope NASA JPL Caltech Archived from the original on 13 March 2014 Retrieved 13 January 2017 External links editIRAC website by the Harvard Smithsonian Center for Astrophysics Spitzer Documentation amp Tools IRAC by the Infrared Science Archive Retrieved from https en wikipedia org w index php title Infrared Array Camera amp oldid 1135089908, wikipedia, wiki, book, books, library,
