Photometric system

In astronomy, a photometric system is a set of well-defined passbands (or optical filters), with a known sensitivity to incident radiation. The sensitivity usually depends on the optical system, detectors and filters used. For each photometric system a set of primary standard stars is provided.

A commonly adopted standardized photometric system is the Johnson-Morgan or UBV photometric system (1953). At present, there are more than 200 photometric systems.

Photometric systems are usually characterized according to the widths of their passbands: broadband (passbands wider than 30 nm, of which the most widely used is Johnson-Morgan UBV system) intermediate band (passbands between 10 and 30 nm wide) narrow band (passbands less than 10 nm wide)

Photometric letters Each letter designates a section of light of the electromagnetic spectrum; these cover well the consecutive major groups, near-ultraviolet (NUV), visible light (centered on the V band), near-infrared (NIR) and part of mid-infrared (MIR). The letters are not standards, but are recognized by common agreement among astronomers and astrophysicists.

The use of U,B,V,R,I bands dates from the 1950s, being single-letter abbreviations.

With the advent of infrared detectors in the next decade, the J to N bands were labelled following on from near-infrared's closest-to-red band, I.

Later the H band was inserted, then Z in the 1990s and finally Y, without changing earlier definitions. Hence, H is out of alphabetical order from its neighbours, while Z,Y are reversed from the alphabetical – higher-wavelength – sub-series which dominates current photometric bands.

FilterLetter Effective Wavelength Midpointλeff for Standard FilterBinney, J.; Merrifield M. Galactic Astronomy, Princeton University Press, 1998, ch. 2.3.2, pp. 53 Full width at half maximum (archetypal Bandwidth) (Δλ) Variant(s) Description Ultraviolet U 365 nm 66 nm u, u', u* "U" stands for ultraviolet. Visible B 445 nm 94 nm b "B" stands for blue. G 464 nm 128 nm g, g' "G" stands for green. V 551 nm 88 nm v, v' "V" stands for visual. R 658 nm 138 nm r, r', R', Rc, Re, Rj "R" stands for red. Near-Infrared I 806 nm 149 nm i, i', Ic, Ie, Ij "I" stands for infrared. Z 900 nm152 nm z, z' Y1020 nm120 nm y J 1220 nm 213 nm J', Js H 1630 nm 307 nm K 2190 nm 390 nm K Continuum, K', Ks, Klong, K8, nbK L 3450 nm 472 nm L', nbL' Mid-Infrared M 4750 nm 460 nm M', nbM N 10500 nm 2500 nm Q 21000 nm Handbook of Geophysics and the Space Environment 1985, Air Force Geophysics Laboratory, 1985, ed. Adolph S. Jursa, Ch. 25, Table 25-1 5800 nm Q'

Note: colors are only approximate and based on wavelength to sRGB representation (when possible).

Combinations of these letters are frequently used; for example the combination JHK has been used more or less as a synonym of "near-infrared", and appears in the title of many papers. Example of use of J for "near-infrared"

Filters used The filters currently being used by other telescopes or organizations.

Units of measurements: Å = Ångström nm = nanometre μm = micrometre

NameFiltersLink2.2 m telescope at La Silla, ESOJ = 1.24 μmH = 1.63 μmK = 2.19 μmL' = 3.78 μmM = 4.66 μmN1 = 8.36 μmN2 = 9.67 μmN3 = 12.89 μm2.2 m telescope at La Silla, ESOA study of the Chamaeleon I dark cloud and T-association. II – High-resolution IRAS maps around HD 97048 and 97300, Assendorp, R.; Wesselius, P. R.; Prusti, T.; Whittet, D. C. B., 19902MASS/PAIRITELJ = 1.25 μmH = 1.65 μmKs = 2.15 μmTwo Micron All-Sky Survey, Peters Automated InfraRed Imaging TELescopeCFHTLS (Megacam)u* = 374 nmg' = 487 nmr' = 625 nmi' = 770 nmz' = 890 nmCanada-France-Hawaii TelescopeChandra X-ray ObservatoryLETG = 0.08-0.2 keVHETG = 0.4-10 keVChandra X-ray ObservatoryCTIOJ = 1.20 μmH = 1.60 μmK = 2.20 μmL = 3.50 μmCerro Tololo Inter-American Observatory, a division of NOAOCousins RI photometryRc = 647 nmIc = 786.5 nmCousins RI photometry, 1976ADPSthe Dark Energy Camerag = 472.0 nmr = 641.5 nmi = 783.5 nmz = 926.0 nmY = 1009.5 nmCentral wavelengths for bands in the Dark Energy SurveyDESDENISI = 0.79 μmJ = 1.24 μmK = 2.16 μmDeep Near Infrared SurveyEggen RI photometryRe = 635 nmIe = 790 nmEggen RI photometry, 1965ADPSFISN60 = 65.00 μmWIDE-S = 90.00 μmWIDE-L = 145.00 μmN160 = 160.00 μmFar-Infrared Surveyor on board, AKARI space telescopeGaiaG = 673 nmGBP = 532 nmGRP = 797 nmGRVS = 860 nmGaia (spacecraft)GALEXNUV = 175–280 nmFUV = 135–175 nmGALaxy Evolution ExplorerGOODS (Hubble ACS)B = 435 nmV = 606 nmi = 775 nmz = 850 nmAdvanced Camera for Surveys on the Hubble Space TelescopeHAWC+Band 1 = 53 μmBand 2 = 89 μmBand 3 = 154 μmBand 4 = 214 μmHigh-resolution Airborne Wideband Camera+ for SOFIAHDF300 nm450 nm606 nm814 nmHubble Deep Field from the Hubble Space TelescopeIRTF NSFCAMJ = 1.26 μmH = 1.62 μmK' = 2.12 μmKs = 2.15 μmK = 2.21 μmL = 3.50 μmL' = 3.78 μmM' = 4.78 μmM = 4.85 μmNASA Infrared Telescope Facility NSFCAMNSFCAMISAAC UTI/VLTJs = 1.2 μmH = 1.6 μmKs = 2.2 μmL = 3.78 μmBrα = 4.07 μmInfrared Spectrometer And Array Camera at Very Large TelescopeJohnson system (UBV)U = 364 nmB = 442 nmV = 540 nmUBV photometric systemVera C. Rubin Observatory (LSST)LSST filter characteristics taken from https://github.com/lsst/throughputs/blob/master/baseline/ (see the filter_X.dat files) with the limits at half the peak transmission.u = 320.5–393.5 nmg = 401.5–551.9 nmr = 552.0–691.0 nmi = 691.0–818.0 nmz = 818.0–923.5 nmy = 923.8–1084.5 nmVera C. Rubin ObservatoryOMCJohnson V-filter = 500-580 nmOptical Monitor Camera on INTEGRALPan-STARRSg = 481 nmr = 617 nmi = 752 nmz = 866 nmy = 962 nmPanoramic Survey Telescope And Rapid Response SystemProNaOS/SPMBand 1 = 180-240 μmBand 2 = 240-340 μmBand 3 = 340-540 μmBand 4 = 540-1200 μmPROgramme NAtional d'Observations Submillerètrique/Systéme Photométrique Multibande, balloon-borne experimentSloan, SDSSu' = 354 nmg' = 475 nmr' = 622 nmi' = 763 nmz' = 905 nmSloan Digital Sky SurveySPIRIT IIIBand B1 = 4.29 μmBand B2 = 4.35 μmBand A = 8.28 μmBand C = 12.13 μmBand D = 14.65 μmBand E = 21.34 μmInfrared camera on Midcourse Space ExperimentMSXPSC – Midcourse Space Experiment (MSX) Point Source Catalog, V2.3Spitzer IRACch1 = 3.6 μmch2 = 4.5 μmch3 = 5.8 μmch4 = 8.0 μmInfrared Array Camera on Spitzer Space TelescopeSpitzer MIPS24 μm70 μm160 μmMultiband Imaging Photometer for Spitzer on SpitzerStromvil filtersU = 345 nmP = 374 nmS = 405 nmY = 466 nmZ = 516 nmV = 544 nmS = 656 nmStromvil photometryStrömgren filtersu = 350 nmv = 411 nmb = 467 nmy = 547 nmβ narrow = 485.8 nmβ wide = 485 nmStrömgren photometric systemUKIDSS (WFCAM)Z = 882 nmY = 1031 nmJ = 1248 nmH = 1631 nmK = 2201 nmUKIRT Infrared Deep Sky SurveyVilnius photometric systemU = 345 nmP = 374 nmS = 405 nmY = 466 nmZ = 516 nmV = 544 nmS = 656 nmVilnius photometric systemVISTA IRCZ = 0.88 μmY = 1.02 μmJ = 1.25 μmH = 1.65 μmKs = 2.20 μmNB1.18 = 1.18 μmVisible & Infrared Survey Telescope for AstronomyWISEW1 = 3.4 μmW2 = 4.6 μmW3 = 12 μmW4 = 22 μmWide-field Infrared Survey ExplorerXMM-Newton OMUVW2 = 212 nmUVM2 = 231 nmUVW1 = 291 nmU = 344 nmB = 450 nmV = 543 nmXMM-Newton Optical/UV MonitorXMM-Newton User's Handbook Sect. 3.5.3.1XEST SurveyUVW2 = 212 nmUVM2 = 231 nmUVW1 = 291 nmU = 344 nmB = 450 nmV = 543 nmJ = 1.25 μmH = 1.65 μmKs = 2.15 μmSurvey includes the point source of 2MASS with XMM-Newton OM Note: colors are only approximate and based on wavelength to sRGB representation (when possible).

Photometric system

Bron en licentie