tmtsoftware / dms-irgsc

IR Guide Star Catalog

TMT-IRGSC

Introduction

This is a python repository dedicated to the development of the Near-Infrared Guide Star Catalog (IRGSC) for the Adaptive Optics (AO) observations of the Thirty Meter Telescope (TMT) project. This package generates the catalog by computing the NIR magnitudes of the optical stellar sources in the PANSTARSS DR2 data. The details of this work can be found in the phase_III_report.pdf file.

Packages

irgsctool:

This is a python package aimed to compute the NIR magnitudes of the optical sources in the PANSTARRS stack-photometric data by modelling them with the Kurucz, Castelli-Kurucz and Phoenix stellar atmospheric models. This package also validates the computed NIR magnitudes with the observed NIR data from UKIDSS (if it is available). The methodology implemented in this python package is implemented on twenty test-fields across the TMT's observable sky and the generated as well as validated IRGSC is available in the generated_irgsc directory (seec details below). Most of the sources have the computed NIR magnitudes similar to the observed. The generated catalog contains astrometric information from GAIA DR3 also. Read the section below to see the nature of generated and validated IRGSC.

Nature of the generated IRGSC

The IRGSC generated has various information about the sources shown in the following Table. This table describes the columns in the IRGSC generated for a particular test field. The details of the flags, e.g., infoflags, filterflags, and qualityflags can be found here. These flags indicate various values assigned to the source by the PANSTARRS team, which gives further information about the nature of the source and the quality of its detection, which can help understand more about a particular object of interest. It is to be noted that although this package relies on the PANSTARRS StackObjectView table, the Right Ascension and Declination of the source is obtained from the mean photometric information as they are well calibrated using Gaia DR2.

Column Name	Description	Data Type
PS1_ObjID	Source identifier in the PANSTARRS data	float
PS1_ra	Right Ascencion of the source in the PANSTARRS DR2 weighted mean photometry	float
PS1_ra_error	Uncertainty in PS1_ra	float
PS1_dec	Declination of the source in the PANSTARRS DR2 weighted mean photometry	float
PS1_dec_error	Uncertainty in the PS1_dec	float
PS1_gpsf	psf magnitude of the source in the g-band stacked photometry	float
PS1_gpsf	Uncertainty in PS1_gpsf
PS1_rpsf	psf magnitude of the source in the r-band stacked photometry	float
PS1_rpsf	Uncertainty in PS1_rpsf	float
PS1_ipsf	psf magnitude of the source in the i-band stacked photometry	float
PS1_ipsf	Uncertainty in PS1_ipsf	float
PS1_zpsf	psf magnitude of the source in the z-band stacked photometry	float
PS1_zpsf	Uncertainty in PS1_zpsf	float
PS1_ypsf	psf magnitude of the source in the y-band stacked photometry	float
PS1_ypsf	Uncertainty in PS1_ypsf	float
SAM_Name	Name of the best-fitted Stellar Atmospheric Model (SAM)	string
Teff	Best-fitted model parameter: Teff	float
logg	Best-fitted model parameter: log(g)	float
[Fe/H]	Best-fitted model parameter: [Fe/H]	float
sam_g	Best-fitted model magnitudes in PANSTARRS g-filter	float
sam_r	Best-fitted model magnitudes in PANSTARRS r-filter	float
sam_i	Best-fitted model magnitudes in PANSTARRS i-filter	float
sam_z	Best-fitted model magnitudes in PANSTARRS z-filter	float
sam_y	Best-fitted model magnitudes in PANSTARRS y-filter	float
sam_j	Best-fitted model magnitudes in PANSTARRS j-filter	float
sam_h	Best-fitted model magnitudes in PANSTARRS h-filter	float
sam_k	Best-fitted model magnitudes in PANSTARRS k-filter	float
scale factor	The scale factor computed after fitting the SAM	float
scale factor error	Error in the computed scale factor	float
d_dev	The parameter denoting the goodness-of-fit	float
Computed J	The computed J magnitude in the Vega system	float
Computed J error	Error in computed J magnitude	float
Computed H	The computed H magnitude in the Vega system	float
Computed H error	Error in computed H magnitude	float
Computed K	The computed K magnitude in the Vega system	float
Computed K error	Error in computed K magnitude	float
gaia source id	Source identifier in Gaia DR3	float
gaia ra	Right Ascension of the source in Gaia DR3 catalog	float
gaia ra error	Uncertainty in gaia ra	float
gaia dec	Declination of the source in Gaia DR3 catalog	float
gaia dec error	Uncertainty in gaia dec	float
gaia parallax	Parallax (mas) of the source in the Gaia DR3 catalog	float
gaia parallax error	Uncertainty in gaia parallax	float
gaia pm	pm of the source (mas/yr) in Gaia DR3 catalog	float
gaia pm ra	pm of the source along R.A. axis in the Gaia DR3 catalog	float
gaia pm ra error	Uncertainty gaia pm ra	float
gaia pm dec	pm of the source along Dec. axis in the Gaia DR3 catalog	float
gaia pm dec error	Uncertainty gaia pm dec	float
gaia ruwe	Renormalised Unit Weight Error flag of the source in Gaia DR3	float
objinfoflag	These flag values of the source in PANSTARRS data specify whether the object is a QSO, transient, asteroid, extended, a known solar system object, etc. in nature	float
objqualityflag	These flag values denote if an object is real or a possible false positive	float
ndetections	The number of times something is detected from the individual exposures	float
nstackdetections	The number of stack detections after which the stack photometric measurements are done	float
ginfoflag	These flags indicate the details of the g filter stack photometry	float
ginfoflag2	These flags indicate the details of the g filter stack photometry	float
ginfoflag3	These flags indicate the details of the g filter stack photometry	float
rinfoflag	These flags indicate the details of the r filter stack photometry	float
rinfoflag2	These flags indicate the details of the r filter stack photometry	float
rinfoflag3	These flags indicate the details of the r filter stack photometry	float
iinfoflag	These flags indicate the details of the i filter stack photometry	float
iinfoflag2	These flags indicate the details of the i filter stack photometry	float
iinfoflag3	These flags indicate the details of the i filter stack photometry	float
zinfoflag	These flags indicate the details of the z filter stack photometry	float
zinfoflag2	These flags indicate the details of the z filter stack photometry	float
zinfoflag3	These flags indicate the details of the z filter stack photometry	float
yinfoflag	These flags indicate the details of the y filter stack photometry	float
yinfoflag2	These flags indicate the details of the y filter stack photometry	float
yinfoflag3	These flags indicate the details of the y filter stack photometry	float
SAM	The name of the best-fitted Stellar Atmospheric Model (SAM)	string

Nature of the IRGSC validated using the UKIDSS Data

The computed NIR magnitudes of the sources in the IRGSC can also be validated using the readily available UKIDSS data (if any) for the given field. irgsctool first checks whether a validated IRGSC can be produced for a given field and alerts the user accordingly. The table below shows the additional columns in an validated IRGSC.

Column Name	Description	Data Type
diff_J	Difference in the observed and computed J	float
diff_H	Difference in the observed and computed H	float
diff_K	Difference in the observed and computed K	float
J_UKIDSS	Observed J	float
err_J_UKIDSS	Uncertainty in observed J	float
H_UKIDSS	Observed H	float
err_H_UKIDSS	Uncertainty in observed H	float
K_UKIDSS	Observed K	float
err_K_UKIDSS	Uncertainty in observed K	float

Application of irgsctool on fields

The method developed for the generation of IRGSC has applied on twenty test fields (see the following table) across the sky. The generaed IRGSC is also valiated using the UKIDSS data available for those fields and the generated as well as validated catalog for these fields can be found in the 'generated_irgsc' directory. In addition to the twenty test fields, additional ten catalogs are provided for the PANSTARRS Medium Deep Survey (MDS) Fields (more information available here). Since the MDS data is not publically released by the PANSTARRS, the optical data to generate the IRGSC for these fields is been taken from the PANSTARRS $3\pi$-survey.

R.A.	Decl.	l	b	E(B-V)
227.26	0.0	359.27	47.24	0.04
334.27	0.38	63.08	-43.84	0.07
60.00	1.25	188.72	-36.53	0.26
30.00	0.50	156.53	-57.82	0.02
11.16	7.83	120.00	-55.00	0.04
225.53	2.19	0.00	50.00	0.04
269.93	-13.48	15.00	5.00	0.98
334.80	50.96	100.00	-5.00	0.28
324.09	51.47	95.00	-0.50	2.48
298.02	34.02	70.00	3.00	1.01
0.00	0.00	96.33	-60.18	0.02
34.50	-5.16	169.97	-59.87	0.01
36.25	-4.50	171.65	-58.22	0.02
164.25	57.66	148.39	53.43	0.04
66.75	15.86	180.08	-22.32	0.58
82.25	-2.60	205.62	-19.48	0.62
189.83	0.00	296.33	62.71	0.01
150.25	10.00	227.71	46.40	0.03
15.0	0.90	127.47	-61.89	0.02
35.0	-3.50	168.62	-58.28	0.01

The generated_irgsc directory contains following sub-directories:

1. results_presented_in_the_report:

This directory contains the generated and validated IRGSC for the 20 test fields using the PANSTARRS data for 30 arcmin radius downloaded from MAST CasJobs. There are several sub-directories and are named according to the name of the test fields eg. tf1, tf2, etc. Each sub-directory contains the results for that particular test field presented in the report. Due to overcrowding of sources in the fields close to the galactic plane fields, these fields have a radius size of 5 arcmin and the results for these fields can be found in results_for_the_fields_close_to_the_galactic_plane sub-directory.

2. partial_irgsc_for_the_test_fields:

This directory contains the generated and validated IRGSC for the 20 test fields using the PANSTARRS data for 35 arcmin radius (or 1.06 sq. deg.) fields as per the work-package requirement. The naming convention is similar to the former directory.

3. partial_irgsc_for_the_mds_fields:

This directory contains generated and validated IRGSC for the PANSTARRS Medium Deep Survey fields with the optical data obtained using pyvo. Due to limitations of pyvo, the data can only be obtained for 15 arcmin radius area of the field. The cordinates of these fields and naming is similar to the name given in the Table (7) of Chambers et.al..

Requirements

This package is developed for Python versions above 3.6. It uses various other packages like: astroquery, astropy, matplotlib, astropy, dustmaps, numpy, datetime, requests, and pyvo.

Note: It is recommended to install irgsctool in a fresh environment and requires a stable internet connection to fetch the data.

Installation

1. Using .zip file from GitHub:

Download the .zip file from here and unzip it. Then open the directory in terminal and type:

pip install .

2. Using the Development version from GitHub:

pip install [email protected]:tmtsoftware/dms-irgsc.git

Usage

 class GenerateIRGSC

This class is defined by importing irgsctool module and passing the R.A. and Decl. arguments. In this package, the catalog is generated using the optimal method described in the workpackage report. After initializing, this module alerts the user if there is no observed NIR UKIDSS data for the given field.

from irgsctool import GenerateIRGSC as GC
gc = GC(ra(float),dec(float))
gc.generate_irgsc()

The module Generate_IRGSC is the module that generates the catalog in .csv format. Irrespective of whether UKIDSS data is available or not, this module (the command gc.generate_irgsc()) generates the catalog using the optical PANSTARRS data from 3pi steradian survey for given ra (float) and decl.(float). The name of the generated catalog has IRGSC prefix followed by RA, Dec., and the data of generation. eg. IRGSC_RA_0_0_DEC_0_0.csv for (ra,dec) = (0.0, 0.0)

class Validate

from irgssctool import Validate vd = Validate(ra,dec) vd.validate()

The module Validate(ra,dec) is the module that validates the computed NIR magnitudes after importing the IRGSC library. If initialized without generating the catalog, this module independantly checks whether the UKIDSS observed NIR data can be obtained for the given field.

# Conclusion/Disclaimer

Please add the following acknowledgment if you use our package in your work.

"This work has made use of "irgsctool" developed as part of the Thirty Meter Telescope (TMT) project."

If you have any questions or suggestions for improvements to this repo,
please email: [email protected]

dms-irgsc's Issues

Add field identification to all generated files

It would be useful if the generated figures and csv files had the ra and dec in both the name of the file and in the content.
The source files seem to have this, but not the generated files. The figures should have the field ra and dec and field size. An example of a file without identification is attached.