national virtual aeronomical observatory brian sharpee molecular physics laboratory sri...

National Virtual Aeronomical Observatory

Brian SharpeeMolecular Physics LaboratorySRI International

NASA AISRP MeetingNASA Ames, April 6, 2005

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1) What is the NVAO?

A “virtual observatory”, allowing the observation of the earth’satmosphere with astronomical instrumentation withoutphysically traveling to an observatory.

A catalog of sky spectra taken with astronomical instrumentationfrom numerous telescopes.

An interactive interface to directly derive scientificinformation from cataloged spectra.


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Planetary Nebula: IC 418

Reduced spectrum of IC 418 in vicinity of neutral oxygen "green” line at 557.7 nm

2) Why does the atmosphere glow at night?



During day: sunlight disassocaites molcules and ionizes atoms.

O O

O2 O+ ,NO+

O, N2

O2,

OH



At night ions, atoms, molecules recombine:

O + O + N2/CO

2 N

2/CO

2 + O

2*

O2* + O O

2 + O(1S)

O3 + H O

2 + OH(v=1-9)

NO+ + e- O +N(2D) O

2+ + e- O + O(1D, 1S)

OO

O2

*

N2

N2

O+ ,NO+O, N

2

O2,

OH



OH* OH(v>=0)+h(480-3000 nm)O2* O2/O2* + h(260-1270 nm)O(1S) O(1D) + h(557.7 nm)Na(2P) Na + h(589.0,589.6 nm)O(1D) O+ h(630.0,636.0 nm)N(2D) N+h(519.8,520.0 nm)

Excited atoms and molecules quenched or radiate:

O+ ,NO+O, N

2

O2,

OH


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3) Why study the nightglow?

Provides information on the chemistry, kinetics, and density distributions of species producing nightglow. => templates for atmospheric models

Measurement of fundamental atomic parameters(wavelengths, spontaneous emission coefficients).

Astronomical sky spectra offer high spectral resolution,dispersion, sensitivity, simultaneous bandwidth unavailableto aeronomers for the study of the nightglow.

Nightglow: Emission from excited ions, atoms, and molecules that “relax”/radiate at night

All-sky OH nightglow emission (Taylor, Pendelton, and Gardner, Adv. Space Res., 2001)

15 papers investigating the quiet night-time atmosphere, published bySRI investigators using astronomical spectra of the nightglow


SRI

Archives

2. Reduction Software

Database

Toolbox

3. NVAO Facility/Interactive Interface

16

Visualization/Manipulation

BrowserQuery

Data

5) NVAO Design

1. Data Sources


Planetary Nebula IC 418CTIO Blanco 4 meter echelle spectrum

nebular emission line

nightglow emission line

5) NVAO Design – Data Sources

Individual high spectral ordersat resolution ()=4000-100000

Observed range per image = 100-800 nm


Echelle Spectra:

SRI

Archives

PRESENT NVAO DATABASE CONTENTS AND STATUS

All data fully extracted and wavelength calibrated to better than 0.001 nm at 750 nm

Small subset of ESI spectrograph data absolute flux calibrated

HIRES

ESI

5) NVAO Design – Data Sources


5) NVAO Design: Data Sources

SMOKA (Subaru) Archive: (Manua Kea, Hawaii) Telescopes: 8.2 meter, Okayama Obs. 1.88 meter Instruments: Faint Object Camera (long slit), HDS (echelle), HIDES (echelle)

5000 spectra from medium to high resolution instrumentation.

Issac Newton Group (ING) Archive: (La Palma, Canary Islands) Telescopes: William Herschel 4.2 meter, Issac Newton 2.5 meter Instruments: OASIS, ISIS (long-slit/echellette), UES (echelle)

Significant fraction of 430,000 total observations are spectra.

European Southern Observatory (ESO) Archive: (La Silla, Paranal, Chile) Telescopes: VLT 4 x 8.2 meter, NTT 3.5 meter, 3.6 meter, 2.2 meter Instruments: FEROS (fiber echelle), UVES (fiber echelle), CES (fiber echelle)

SPECTRA ARCHIVES

Archives under development for GEMINI North and South (Mauna Kea, Chile) Keck Observatory (Mauna Kea), HET/McDonald Observatory (Texas)

SRI

Archives


Spectra stored most often as “raw” files (FITS) directas recorded from CCD

No real time transfer of spectra from archives available

Associated spectra for calibration also stored as raw files

instrumental signature removal, detector biases and individual pixel responses determination, correction for CCD defects

wavelength calibration, absolute intensity calibration


5) NVAO Design: Reduction Software



5) NVAO Design: Reduction Software

“Pipeline” (Mostly Automated) Calibration:

Keck/HIRES and ESI: MAKEE (T. Barlow)

VLT/UVES: Built into MIDAS (ESO)

Full reduction and calibration to wavelength determination

Full reduction to intensity calibration

Manual Reduction and Calibration:

Image Reduction and Analysis Facility (IRAF):National Optical Astronomical Observatories (NOAO)

Custom written Perl and Fortran codeusing CFITSIO code (NASA Goddard – HEASARC)


Database Attributes of sky spectra stored inMySQL database upon completionof their reduction and calibration

Computes and sorts attributes by common aeronomic and astronomic

Dst/Kp indices, shadow height, solar depression angle,right ascension, declination, moon brightness

BrowserPerl/CGI web form for forming aquery to select spectra based uponcommon aeronomic and astronomicparameters:


5) NVAO Design: Interactive Interface

Toolbox


Tools that operate on spectra selected from databaseby browser query: (written in Perl) => Peak detection, line profile fitting, intensity measurement => Line measurement collation by aeronomical parameter => Calculation of physical parameters from collections of line detections and measurements

i.e. mesopausal temperature

Manipulation of output data products from toolbox: (output spectra, line intensity measurements vs. physical parameters) for plotting or interactive measurement on-line

(written in Perl, using PGPLOT)




NVAO will make available this spectra to the whole aeronomy/astronomy communities

Build a Virtual Observatory: suite of analysis tools that allow users toperform "experiments" or ask "questions" of the data:

=> How do multiple mesopausal temperatures compare with time of night? => What trends exist between two features with time of night/season/ geographic location? => What else was going on when I was measuring a particular atmospheric parameter with another instrument (such as Na LIDAR)?

Emphasize easy accesibility via interactive web tools: immediate “science” with minimal user effort (isolate reduction/ calibration details)


Browser Database Toolbox

“Return a spectrum showing N(2D-4S) 519.8 nm on June 3, 2000 at any time between UT 8-10 at Mauna Kea, HI (Keck)”

Query:

ASCII file(intensity vs. wavelength)

Data:

Sample Query #1:



Browser Database

Toolbox

“Return a spectrum showing N(2D-4S) 519.8 nm on June 3, 2000 at any time between UT 8-10 at Mauna Kea, HI (Keck) for interactive measurement”

Query:

Sample Query #2: Visualization/Manipulation



Browser Database

Toolbox

“Plot the mesospheric temperature from v=9 OH Meinel band system lines over all nights 21-25 October 2000 from Mauna Kea, Hawaii (Keck)”.

Query:

Sample Query #3: Visualization/Manipulation



Acquired additional data from Keck/HIRES, VLT/UVES, HET/HRS

Acquired and adapting VLT/UVES pipeline for additional instruments

Completed

Basic tools (line detection/measurement) completed, somemore advanced tools (temperature determination) also completed

Simple interface for interacting with database/downloading ASCII spectrum files completed.

Written

Database

Toolbox


Browser

Data Sources

Reduction Software


5) NVAO Status

1) Get simplified browser/database interface on-line for downloading reduced spectra

2) Adapt pipelines (MAKEE and UVES) for use with potential archival spectrum sources

3) Translate display/data manipulation tools written in Perl to Javascript for incorporation into web interface

4) Develop more sophisticated query language and associated browser/database interface to allow more elaborate queries for science derivation


5) NVAO Immediate/Long-Term Plans

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