Good UNM Telescopes and Good UNM Telescopes and the Evil Atmospherethe Evil Atmosphere
John McGrawJohn McGraw
A Talk in the Universe ofA Talk in the Universe ofGood and EvilGood and Evil
The Obscure UniverseThe Obscure Universe The Good – Fundamental new capability to The Good – Fundamental new capability to
understand the universeunderstand the universe Why we want excellent ground-based telescopesWhy we want excellent ground-based telescopes
UNM Initiatives in Ground-based AstronomyUNM Initiatives in Ground-based Astronomy The Evil – The Earth’s atmosphere interferes with The Evil – The Earth’s atmosphere interferes with
ground-based optical/IR observations in a number ground-based optical/IR observations in a number of waysof ways
The Obscure UniverseThe Obscure Universe Two causes of obscuration:Two causes of obscuration:
Physical obscuration – dust!Physical obscuration – dust! Inability to observe – observational blindness.Inability to observe – observational blindness.
Simultaneous optical/infrared time-Simultaneous optical/infrared time-resolved synoptic observationsresolved synoptic observations
The Obscure UniverseThe Obscure Universe
Discovery of Discovery of QuasarsQuasars
Quasar LensingQuasar Lensing
AGN AGN ReverberationReverberation
The Obscure UniverseThe Obscure Universe
The Nature of The Nature of QuasarsQuasars
The Obscure UniverseThe Obscure Universe
The “Standard Model”The “Standard Model” Accretion disc scale ~ 1 pcAccretion disc scale ~ 1 pc
The Obscure UniverseThe Obscure Universe
AGN phenomenon AGN phenomenon is ubiquitousis ubiquitous Milky Way?Milky Way? All galaxies?All galaxies? Evolution?Evolution?
The Obscure UniverseThe Obscure Universe
Mapping: Model, Orientation, Time HistoryMapping: Model, Orientation, Time History Light travel timescale ~ 3 yearsLight travel timescale ~ 3 years Dynamical timescale ~ r/V ~ 10 – 100 yearsDynamical timescale ~ r/V ~ 10 – 100 years
The Obscure UniverseThe Obscure Universe
The outsider’s view The outsider’s view of gravitational of gravitational lensing:lensing:
The Obscure UniverseThe Obscure Universe
Geometry of Geometry of Different Optical Different Optical pathspaths Source geometrySource geometry Lens geometryLens geometry Source dust chemistrySource dust chemistry
Well-sampled light Well-sampled light curvescurves Optical path length Optical path length
measurementmeasurement Effects of microlensingEffects of microlensing Dust in lensesDust in lenses
The Obscure UniverseThe Obscure Universe
Luminosity Luminosity variabilityvariability Days to yearsDays to years
Intrinsic variabilityIntrinsic variability Optical path lengthOptical path length MicrolensingMicrolensing
Colley et al. 2002Colley et al. 2002
The Obscure UniverseThe Obscure Universe
AGN ReverberationAGN Reverberation Mapping the scale, structure, and Mapping the scale, structure, and
time-dependent structure changes time-dependent structure changes in the environs of massive black in the environs of massive black holesholes
Testing the standard model of AGNsTesting the standard model of AGNs Examples: N1275, N7742Examples: N1275, N7742
The Obscure UniverseThe Obscure Universe
CTICTI 1.8-m, f/2.2 meridian 1.8-m, f/2.2 meridian
transit telescopetransit telescope Images formed on Images formed on
multiple detectors multiple detectors operated in TDI modeoperated in TDI mode
no moving partsno moving parts multiple colors each nightmultiple colors each night
Fully automated operationFully automated operation Photometric imaging over Photometric imaging over
1 - 2° FOV1 - 2° FOV surveys ~120°surveys ~120°22 each each
nightnight VV21.7 (S/N) > 5 nightly 21.7 (S/N) > 5 nightly
detection limitdetection limit
The Obscure UniverseThe Obscure Universe
QuasarsQuasars 1° wide strip, 1° wide strip, αα = 8 hours (NGC) = 8 hours (NGC) 120°² 120°² 25 quasars/°² to B = 21 25 quasars/°² to B = 21 3000 quasars3000 quasars
Conservatism: 2° FOV, tilt to cover 10°, B fainter than Conservatism: 2° FOV, tilt to cover 10°, B fainter than 22 at S/N = 10, 2df data 22 at S/N = 10, 2df data all quasars all quasars
Galaxies (same geometry, B = 19.7)Galaxies (same geometry, B = 19.7) 18000 galaxies18000 galaxies
SNe (same geometry, B = 21 point source)SNe (same geometry, B = 21 point source) 100 ~ SNe/year100 ~ SNe/year
The Obscure UniverseThe Obscure Universe
A UNM/UT collaboration can A UNM/UT collaboration can address many fundamental address many fundamental questions about the questions about the Obscure Obscure UniverseUniverse..
First year of five funded by First year of five funded by AFRLAFRL
Extinction, Refraction and Extinction, Refraction and TurbulenceTurbulence
From Earth’s AtmosphereFrom Earth’s Atmosphere The atmosphere is a The atmosphere is a
turbulent, absorbing, turbulent, absorbing, refractive medium refractive medium that must be that must be considered part of considered part of the optical system of the optical system of any telescope.any telescope. System design trade-System design trade-
offs: perhaps not too offs: perhaps not too bad!bad!
Effects of Earth’s Effects of Earth’s AtmosphereAtmosphere
Three layers in the Earth’s atmosphere contribute to turbulenceThree layers in the Earth’s atmosphere contribute to turbulence Surface layerSurface layer Planetary boundary layerPlanetary boundary layer Upper atmosphereUpper atmosphere
We can do something about the surface layer!We can do something about the surface layer!
Effects of Earth’s Effects of Earth’s AtmosphereAtmosphere
)()(
)(1080)( 22
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hThPhC Tn
Refractive Index Refractive Index Structure ConstantStructure Constant
Where:Where: P(h) is pressure in millibarsP(h) is pressure in millibars T(h) is temperature in KelvinT(h) is temperature in Kelvin h is height in metersh is height in meters r is sensor separation in metersr is sensor separation in meters p is position at h separated by rp is position at h separated by r
221 )()(),( pTpThrDT
3/22 )(),( rhChrD TT
Effects of Earth’s Effects of Earth’s AtmosphereAtmosphere
Microthermal testingMicrothermal testing 1-m separation1-m separation Probes spaced in Probes spaced in
altitudealtitude 250 Hz digital 250 Hz digital
samplingsampling
Effects of Earth’s Effects of Earth’s AtmosphereAtmosphere
Microthermal Microthermal measurementsmeasurements Sunrise neutral eventSunrise neutral event Convective/radiative transportConvective/radiative transport
Effects of Earth’s Effects of Earth’s AtmosphereAtmosphere
Surface Layer Atmospheric Surface Layer Atmospheric Turbulence Differential Image Turbulence Differential Image Motion MonitorMotion Monitor SLAT-DIMMSLAT-DIMM
Sources matched to sub-aperturesSources matched to sub-apertures DIMM techniqueDIMM technique Doesn’t assume atmospheric modelDoesn’t assume atmospheric model
Provisional patent in progressProvisional patent in progress
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Heat source shut off hereAdded turbulence from
lab personnel
Heat source on
Heat source off Image Motion dominated by centroid noise
Effects of Earth’s Effects of Earth’s AtmosphereAtmosphere
LIDAR Saves AstronomyLIDAR Saves Astronomy Small, inexpensive lidar Small, inexpensive lidar
to monitor atmospheric to monitor atmospheric transparency in real-timetransparency in real-time
““Engineering data Engineering data stream”stream”
Multiple use modesMultiple use modes NSF proposal – Georgia NSF proposal – Georgia
TechTech
Effects of Earth’s Effects of Earth’s AtmosphereAtmosphere
Real-time pupil Real-time pupil curvature curvature measurementsmeasurements
Real-time image Real-time image PSF measurementsPSF measurements
Pupil phase Pupil phase reconstruction?reconstruction?
Our GoalsOur Goals Site selection for CTISite selection for CTI Help optimize HETHelp optimize HET Transparency monitor Transparency monitor
(lidar) at CTI(lidar) at CTI Real-time image Real-time image
reconstructionreconstruction Access to telescopes Access to telescopes
for UNMfor UNM Investigate the Investigate the
Obscure UniverseObscure Universe