Overview
You have to take two images of each area for automatic new object survey.
And you had better have the past images of the same area.
Stars not recorded in star catalog (ND) output by the PIXY system are classified into the following four types.
- New objects
- Bright variable star
- Normal star not recorded in star catalog
- False detection
Here you have to identify with known variable stars following the steps in the Identification in advance.
So the 2. Bright variable star can be rejected.
Then 4. False detection are rejected.
If there are two images of the same area at the almost same time, the real stars (1. New objects or 3. Normal star not recorded in star catalog) should be detected on both images at the same position as the same brightness.
On the other hand, 4. False detection will be rarely detected on both images at the same position as the same brightness.
Therefore, the system investigates all images at one night and judged ND stars only detected from several images at the same position as the same brightness as real stars.
It rejects other ND data only detected from one image as false detection.
Among the real stars, 1. New objects will not be detected from the past images, but 3. Normal star not recorded in star catalog will be detected on the past images at the same position as the same brightness.
Therefore, the system also investigates past images and judges if the real stars are new objects or not.
After these processes, only candidates of new objects are remained.
By the way, when you would like to search new supernovae in this style, please do not add nebulae or clusters data into the identification database as described in the Identification Database Construction.
Supernovae appear near galaxies.
Because the positional error of nebulae or clusters is large, such supernovae will be identified with the host galaxy and rejected automatically.
Execution
Here describes the steps of new object survey using images of the Ageo Survey for example.
First, Ageo Survey team took four images on Dec. 17, 1998 between 9h and 10h in R.A., +10 deg and +20 deg in Decl.
The obtained images are as follows, put in the same folder named 19981217.
19981217/35mm/0900+1000-R-01.mtf
19981217/35mm/0900+2000-R-01.mtf
19981217/35mm/1000+1000-R-01.mtf
19981217/35mm/1000+2000-R-01.mtf
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Examine all images by the PIXY system and create PXF files.
You had better run the PIXY system where the folder 19981217 exists.
Then the image name recorded in the PXF file will be as follows.
19981217/35mm/0900+1000-R-01.mtf
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But if you moved to the folder 19981217/35mm/ and run the PIXY system, the image name recorded in the PXF file will be as follows.
Then you have to set the path of PXF files using -pxf option when running automatic survey program.
The names of PXF files have to be same as the images, just the extension is changed as .pxf.
Finally, the following four PXF files should be created.
19981217/35mm/0900+1000-R-01.pxf
19981217/35mm/0900+2000-R-01.pxf
19981217/35mm/1000+1000-R-01.pxf
19981217/35mm/1000+2000-R-01.pxf
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Then identify all these PXF files with known variable stars following the steps in the Identification.
And register the magnitude data into the database following the steps in the Magnitude Database Construction.
Next time, Ageo Survey team took images of the same area on Jan. 8, 1999.
All the images are put in the same folder 19990108.
19990108/35mm/0900+1000-R-01.mtf
19990108/35mm/0900+2000-R-01.mtf
19990108/35mm/1000+1000-R-01.mtf
19990108/35mm/1000+2000-R-01.mtf
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Examine all images by the PIXY system and create PXF files, identify them with known variable stars, and register them into the magnitude database.
Now you have the following eight PXF files.
19981217/35mm/0900+1000-R-01.pxf
19981217/35mm/0900+2000-R-01.pxf
19981217/35mm/1000+1000-R-01.pxf
19981217/35mm/1000+2000-R-01.pxf
19990108/35mm/0900+1000-R-01.pxf
19990108/35mm/0900+2000-R-01.pxf
19990108/35mm/1000+1000-R-01.pxf
19990108/35mm/1000+2000-R-01.pxf
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Let's search new objects in the images on Jan. 8, 1999.
The new object survey is run by -survey option of the PIXY system.
All PXF files of images taken at one night have to be put in one folder.
Running the system, set the name of the folder.
The result is output on the display.
When setting a file name, the result is also saved in the file.
The automatic new object survey program reads the magnitude database and the image information list.
You must set the property misao.home as the MISAO home directory's path, using -D option of java command.
Here let's see the MISAO home directory as C:\misao.
In this case, type as follows and run the automatic new object survey.
The result will be saved in the file 19990108.chk.
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java -Dmisao.home=C:\misao misao.pixy.Pixy -survey 19990108 19990108.chk
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Result
After automatic new object survey, the detected ND are classified into the three groups.
- Candidates of new objects
A star not detected at all in the past.
- Candidates of variable stars
A star whose magnitude in the past image differs more than 1.0 mag, or a star which has been 1.0 mag or more fainter and not detected (anyway, it has been detected once at least).
- Normal stars
A star which was detected completely in the past and the magnitude has not differed more than 1.0 mag.
- No data in past
A star which has no valid past images, so it cannot be told if it is a new object or not.
Magnitude data are recorded for each ND star.
The data format is quite same as the magnitude database.
The name of each star is based on the R.A., Decl. and the positional error.
Please read Magnitude Database Construction for more details.
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Candidates of new objects
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======================================================================
093941.63+185259.2-102.3
1998 Dec 17.68730 <8.9R 19981217/35mm/0900+2000-R-01.m
tf ( 79.47, 288.33)
1998 Dec 17.70119 <9.0R 19981217/35mm/1000+2000-R-01.m
tf ( 571.19, 321.71)
1999 Jan 8.76706 6.5R 19990108/35mm/0900+2000-R-01.m
tf ND-00001 ( 52.82, 287.70)
1999 Jan 8.77731 6.5R 19990108/35mm/1000+2000-R-01.m
tf ND-00001 ( 564.02, 305.46)
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* Some lines are forced to be folded here.
These data are detected from several images on Jan. 8, 1999 at the same position as the same brightness.
So they are real stars.
The result shows that the former star was not detected from the image on Dec. 17, 1998.
So it may be a new nova or comet.
However, further investigation makes it clear that this star is not a new object but an asteroid Vesta.
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Normal stars
**********************************************************************
======================================================================
093506.95+101429.7-102.3
1998 Dec 17.68655 8.8R 19981217/35mm/0900+1000-R-01.m
tf ND-00024 ( 109.08, 248.30)
1998 Dec 17.70207 8.9R 19981217/35mm/1000+1000-R-01.m
tf ND-00016 ( 620.88, 282.70)
1999 Jan 8.76627 8.8R 19990108/35mm/0900+1000-R-01.m
tf ND-00017 ( 89.82, 239.30)
1999 Jan 8.77824 9.0R 19990108/35mm/1000+1000-R-01.m
tf ND-00019 ( 620.00, 274.99)
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* Some lines are forced to be folded here.
This star was also detected from the image on Dec. 17, 1998, as same brightness.
So it is classifed as a normal star.
Path of PXF files
When PXF files of past images are put in other directories, set -pxf option after -survey option with the path of PXF files.
In the case of example mentioned above, if the PXF files of Dec. 17, 1998 are put in C: drive and the PXF files of Jan. 8, 1999 are put in D: drive, run the system as follows.
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java -Dmisao.home=C:\misao misao.pixy.Pixy -survey 19990108 19990108.chk -pxf C:
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When setting several paths, quote them with " ".
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