MACHO Project: Lightcurve Browser Help

Index

Page Layout

1.0 Help

2.0 Plot

3.0 Options Sidebar

3.1 Zoom & Show input Parameters

3.1.1 X axis (Time MJD)

By default, the midpoint of the current X axis limits is preset.

3.1.2 Y axis (Red Intensity)

By default, the midpoint of the red focal plane's current Y axis limits is preset.

3.1.3 Y axis (Blue Intensity)

By default, the midpoint of the blue focal plane's current Y axis limits is preset.

3.2 Zoom In on

3.2.1 X

The lightcurve is immediately redisplayed.

3.2.2 Y

The lightcurve is immediately redisplayed.

3.2.3 XY

The lightcurve is immediately redisplayed.

3.3 Zoom Out on

3.3.1 X

The lightcurve is immediately redisplayed.

3.3.2 Y

The lightcurve is immediately redisplayed.

3.3.3 XY

The lightcurve is immediately redisplayed.

3.4 Show Data for Time (X axis)

The lightcurve is immediately redisplayed.

3.9 List Dataset

3.5 Units

3.5.1 instr

3.5.2 calib

3.5.3 flux

3.6 Add phasing on redraw

To initiate an immediate redisplay, select Redraw.

3.7 Redraw

3.8 Reset Defaults

The lightcurve is immediately redisplayed.

4.0 Template Attributes

5.0 Show Data Block

6.0 List Dataset Block

Due to data compaction considerations, some floating point fields have been encoded as integers. The data field definitions are presented in the first table; followed by the encryption formulae in the second table.

Label	Description
Date	Date of the observation. Units are Modified Julian Date which is calculated as (JD - 2400000.5).
Obsid	Project identifier for observation.
Pier	Side of pier where telescope was positioned during the observation
Exposure	Length of time of camera exposure. Units are seconds.
Checklist	Flags indicating completion status of observation collection, analysis and archival.
Airmass
rMag	red magnitude
rErr	(red) 1-sigma error
rDS	(red) sky - This is actually = (fit_sky - average_sky)/(tmpl_fit_brightness). The average_sky is subtracted in order to remove the image-to-image variation in the sky background. It is normalized to the tmpl_fit_brightness = 10**(0.4*fit_mag) because it is the ratio which should indicate possible photometry errors. See Real to Integer Conversion table.
rTF	(red) type - Contains some signal to noise (S/N) information on the basis of the DOPHOT criteria for bright stars, faint stars, too low S/N to be called a star. In the later case, SoDOPHOT still reports a magnitude because the star is known to exist due to the template reduction. This also contains information as to whether a star is within 10 pixels of the edge of a chunk (including the "overlap" region) or within 10 pixels of the edge of a template reduction chunk. type meaning 1 bright, unsplit star 2 bright, split star 3 faint, unsplit star 4 faint, split star 5 very faint or unconverged unsplit star 6 very faint or unconverged split star 7 too faint or off the image, unsplit star 8 too faint or off the image, split star 9 unconverged in 7 parameter fit 10 large number of pixels missing (> 35%) 11 cosmic ray 12 galaxy (currently disabled) 13 obiterated star type is encrytpted with a boundary flag: type = type(as above) + 20*(template boundary flag) + 40*(boundary flag) where the (template boundary flag) = 1 for stars within 10 pixels of a template chunk boundary and 0 otherwise. The (boundary flag) = 1 for stars within 10 pixels of a routine reduction chunk boundary, = 2 for stars which fall off the image altogether, and = 0 otherwise.
rCP	(red) crowding - Seeing dependent crowding of a star. A value >= 1 suggests trouble as does a time series with wildly fluctuating values. See Real to Integer Conversion table.
rX2	(red) SoDOPHOT fit chi2. See Real to Integer Conversion table.
rMP	(red) The PSF weighted sum of the pixels that have been removed from the fit due to bad pixels, saturation, and cosmic rays. Large values can occur when a bad column runs through the center of a stars PSF, but not when it skirts the edge. See Real to Integer Conversion table.
rCR	(red) cosmic ray flux - PSF weighted sum of the cosmic rays that SoDOPHOT has detected and removed from subraster being used for the fit. It is normalized to the star brightness (= peak amplitude * PSF_area). If we were doing PSF_weighted aperature photometry, then this number would be the fractional change in the star brightness due to the subtracted cosmic ray. The motivation for this parameter is that quite often, it is found that not all of the cosmic ray is subtracted. In this case, CR_flux would be an upper limit on photometric error due to an unsubtracted piece of a cosmic ray. Alternatively, we might just use it to flag suspicious data. See Real to Integer Conversion table.
rA	(red) amplifier identifier
rXpix	(red) x pixel coordinate
rYpix	(red) y pixel coordinate
rSky	(red) average sky
rFWHM	(red) full-width-half-max of PSF in 0.625" pixels
rTobs	(red) template observation identifier
r	(red) simple cut flag - if either the magnitude or the error is bad, flag = 0; otherwise, flag = 1.
bMag	blue magnitude
bErr	for blue focal plane: see rErr
bDS	for blue focal plane: see rDS
bTF	for blue focal plane: see rTF
bCP	for blue focal plane: see rCP
bX2	for blue focal plane: see rX2
bMP	for blue focal plane: see rMP
bCR	for blue focal plane: see rCR
bA	for blue focal plane: see rA
bXpix	for blue focal plane: see rXpix
bYpix	for blue focal plane: see rYpix
bSky	for blue focal plane: see rSky
bFWHM	for blue focal plane: see rFWHM
bTobs	blue template observation identifier
b	for blue focal plane: see r

Floating Point to Integer Conversion
label	float pt range	integer range	integer encoding
TF		0-99
CR	0.001-10	0-253	63*(log10(max(min(100,float_CR),0.001))+3) + 1
MP	0.001-1	0-253	84*(log10(max(min(1,float_MP),0.001)+3) + 1
X2	10-1.e4	0-253	84*(log10(max(min(1e4,float_X2),10)-1)
CP	0.001-10	0-253	63*(log10(max(min(10,float_CP),0.001))+3) + 1
DS	-100--0.01 0.01-100	-322..322 0.01-100	80*sign(float_DS)*(log10(max(min(100,abs(float_dsky)),0.01))+2) or if abs(float_DS) < 0.01, DS = 0

Acknowledgement to use when referencing MACHO Project data

"This paper utilizes public domain data originally obtained by the MACHO Project, whose work was performed under the joint auspices of the U.S. Department of Energy, National Nuclear Security Administration by the University of California, Lawrence Livermore National Laboratory under contract No. W-7405-Eng-48, the National Science Foundation through the Center for Particle Astrophysics of the University of California under cooperative agreement AST-8809616, and the Mount Stromlo and Siding Spring Observatory, part of the Australian National University."