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Scientific Use Cases to be implemented to

IVOQL

Masahiro Tanaka and JVO team (NAOJ)

IVOA Interoperability 14 May 2003

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Major Query items Fundamental dimensions

position with coordinate system wavelength time flux / apparent magnitude

Other parameters redshift distance (from parallax / photometric / redshift) absolute magnitude …

Attributes object names object types (star / galaxy / …) instrument (telescope / detector / filter / …) …

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Use Cases

1. Follow-up

2. Search for particular objects

3. Search for moving objects

4. Line matching

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Use Case 1: Follow-up

Obtain supplemental data of objects you have observed

Targets Gamma-ray burst Super Nova AGN …

Query Position Time Cross-match

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Example of Query forFollow-up data

select y.id, c.ra, c.dec, c.vmag

from public_catalog c, your_data y,

where XMATCH(c, y) < 5 arcsec and

c.obs_time between

TIME(“2003-05-12 09:00:00”) and

TIME(“2003-05-17 17:00:00”)

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Use Case 2:Search for particular objects

Find unknown objects with particular features

Targets Brown dwarf Gravitational lens Metal-poor stars Binaries, Planetary systems …

Query Color / Line Cross-match

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Example of search forbrown dwarf candidate

Brown dwarf can be observed in IR, not in Visual

select i.id, i.ra, i.dec, i.kmag

from ir_cat i, visual_cat v

where XMATCH(i !v) < 5 arcsec and

i.jmag - i.kmag > 1

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Use Case 3:Search for moving objects

Targets Asteroid Comet …

Query Position Time Cross-matching

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Example of search formoving objects

select c1.ra, c1.dec, c1.vmag,

c2.ra, c2.dec, c2.vmag

from cat1 c1, cat2 c2

where XMATCH(c1, !c2) < 30 arcsec and

XMATCH(!c1, c2) < 30 arcsec and

ABS(c1.vmag - c2.vmag) < 2

cat1 cat2

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Use Case 4:Line matching

select m.molecule, m.mode, m.frequency,

y.strength

from your_data y, lte_model_20K m

where LINEMATCH(y, m) < 0.1 GHz and

y.sn > 3

LINEMATCH can work with Doppler shift.

more than

ABS(m.frequency - y.frequency) < 0.1 GHz

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Summary of Use Cases

Cross-match is essential for astronomical use

XMATCH: in position LINEMATCH: in wavelength or frequency

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Data analysis How to query if columns are not provided?

e.g., only images/spectra are provided Data analysis function will be needed

Data analyses: source/line extraction morphology analysis classification data mining

Open question: VOQL supports data analysis?