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Data Access

SDO/HMI Linewidth, 720-Second Data

(2011). SDO/HMI Linewidth, 720-Second Data [Data set]. Joint Science Operations Center (JSOC), Stanford University. https://doi.org/10.48322/v6me-8w52. Accessed on .

Note: Proper references, including those in BibTex or other formats, should include the "Accessed on date" as shown above to identify the version of the resource being cited in a given publication.

ResourceID
spase://NASA/NumericalData/SDO/HMI/Linewidth_Data/PT720S

Description

The linewidth observable refers to the FWHM of the (assumed) Gaussian absorption line profile for the 6173.3 Å line on the surface of the sun.

HMI samples the Fe I absorption line at 6173.3 Å at six points. Assuming that the "pure" solar Fe I line profile is a Gaussian, and the HMI filter filter transmission profiles are delta functions, the first and second Fourier coefficients of the of the Fe I line can be calculated and an estimate of the Doppler Velocity can be made. An estimate (proxy) for the continuum intensity Ic is obtained by "reconstructing" the solar line from the estimates of the Doppler shift λo, the linewidth σ, and the linedepth Id. More details can be found at http://jsoc.stanford.edu/relevant_papers/observables.pdf.

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Details

Version:2.6.1

NumericalData

ResourceID
spase://NASA/NumericalData/SDO/HMI/Linewidth_Data/PT720S
ResourceHeader
ResourceName
SDO/HMI Linewidth, 720-Second Data
DOI
https://doi.org/10.48322/v6me-8w52
ReleaseDate
2024-11-01 00:08:46
RevisionHistory
RevisionEvent
ReleaseDate
2024-11-01 00:08:46
Note
Metadata created by SY
RevisionEvent
ReleaseDate
2024-11-18 00:08:46
Note
Added DOI by SY
Description

The linewidth observable refers to the FWHM of the (assumed) Gaussian absorption line profile for the 6173.3 Å line on the surface of the sun.

HMI samples the Fe I absorption line at 6173.3 Å at six points. Assuming that the "pure" solar Fe I line profile is a Gaussian, and the HMI filter filter transmission profiles are delta functions, the first and second Fourier coefficients of the of the Fe I line can be calculated and an estimate of the Doppler Velocity can be made. An estimate (proxy) for the continuum intensity Ic is obtained by "reconstructing" the solar line from the estimates of the Doppler shift λo, the linewidth σ, and the linedepth Id. More details can be found at http://jsoc.stanford.edu/relevant_papers/observables.pdf.

PublicationInfo
Authors
The HMI Consortium: Stanford University (USA); NASA Goddard Space Flight Center (USA); Lockheed Martin Solar and Astrophysics Laboratory (USA); National Center for Atmospheric Research (USA);
PublicationDate
2011-01-21 00:00:00
PublishedBy
Joint Science Operations Center (JSOC), Stanford University
Contacts
RolePersonStartDateStopDateNote
1.PrincipalInvestigatorspase://SMWG/Person/Philip.H.Scherrer
2.GeneralContactspase://SMWG/Person/Rick.Bogart
InformationURL
Name
The HMI website at Stanford
URL
http://hmi.stanford.edu/
InformationURL
Name
The SDO/HMI Instrument paper
URL
https://doi.org/10.1007/s11207-011-9834-2
AccessInformation
RepositoryID
spase://SMWG/Repository/Stanford/HMI-AIA.JSOC
Availability
Online
AccessRights
Open
AccessURL
Name
JSOC Data Center
URL
http://jsoc.stanford.edu/ajax/lookdata.html?ds=hmi.Lw_720s[2020-01-01T00:00:00/60m]
Style
Search
Description

Change the date and the time to find the HMI data.

AccessURL
Name
SDO/HMI Data Search via Virtual Solar Observatory
URL
https://sdac.virtualsolar.org/cgi/search?time=1&instrument=HMI&spectrum=1&version=current&build=1
Description

VSO path to JSOC-resident SDO HMI data files

Format
FITS
InstrumentIDs
spase://SMWG/Instrument/SDO/HMI
MeasurementType
ImageIntensity
TemporalDescription
TimeSpan
StartDate
2010-04-24 19:11:26
RelativeStopDate
-P3D
Cadence
PT720S
ObservedRegion
Sun
ObservedRegion
Sun.Photosphere
Parameter #1
Name
FITS Data Array
Description

Linewidth

Cadence
PT720S
CoordinateSystem
CoordinateRepresentation
Cartesian
CoordinateSystemName
HPC
Wave
WaveType
Photon
WaveQuantity
Wavelength
WavelengthRange
Low
6173
High
6173
Units
angstrom
SpatialCoverage
CoordinateSystem
CoordinateRepresentation
Cartesian
CoordinateSystemName
HPC
Description

Array size: 4096x4096
Pixel Resolution: 0.504 arcsec