Gaia Science Alerts Working Group - User contributions [en]

Triggers:FUOri

2013-07-24T15:09:23Z

Aleks.scholz:

== Eruptive YSOs ==

Prototypes:

FU Oris are an extreme subsample of eruptive classical T Tauri stars. Only one outburst observed, but lasts for decades. Only about a dozen FU Ori bursts observed. V1647 Ori is illuminating a McNeil's nebula in the vicinity of NGC 2068 star-forming region.

[[File:FUOri.png]]
Plot from [http://www.ta3.sk/caosp/Eedition/FullTexts/vol36no3/pp149-157.pdf D.Chochol et al. 2006].

EX Lupis (EXors) have smaller, shorter, recurrent outbursts.

[[File:ExLupi.png|right|400px|thumb|EX Lupi photometry from the ASAS project.]]

OO Ser was discovered in 1994 and is similar to FUors and EXors, but is so deeply embedded, that at its brightest was not visible in J band ([http://ukads.nottingham.ac.uk/abs/1996ApJ...468..861H Hodapp et al. 1996]).
It was observed in infrared with ''Infrared Space Observatory'' and Spitzer ([http://arxiv.org/abs/0705.1231 Kospal et al. 2007]).
It has different time scales than FUors and EXors, is rather a ''fast'' FUor (similar to V1647 Ori) with a time of rise of about 8 months.

Characteristics:

* diverse zoo of lightcurves, use of templates is risky
* many details unknown, unbiased sample required
* rise time varies from months to years
* amplitude range from <1 mag to 5 mag (but 1mag cutoff is probably useful)
* outburst last from months to decades, some are recurrent
* extreme events like FU Ori are very rare
* Spectra: F or G supergiants, red, heavily veiled continuum with strong emission of <math>H_{\alpha}</math>
* At maximum spectral types are in the range Ae(alpha) - Gpe(alpha)
* X-ray variability present
* FU Ori and V1057 Cyg rise over 1 yr, whereas V1515 Cyg rise over 20 years
* FU Ori and V1515 Cyg decline over 20-100 years, V1015 Cyg decays faster (10 yrs)

Trigger is necessary, because immediate follow-up (on timescales of weeks) needed to study the impact of
such accretion bursts on the properties of the dust and gas in the disks. Also, high cadence monitoring
immediately after the event is useful for modeling the source.

Identification:
* >1mag rise in magnitude
* red spectrum, any spectral type
* J-K>1. IR excess, UV excess
* IRAC3 [5.8mu] - IRAC4 [8.0mu] > 0.4
* WISE1 [3.5mu] - WISE4 [22mu] > 2.0
* WISE1 [3.5mu] - WISE2 [4.5mu] > 0.3 (weak criterion)
* Halpha emission

References:

* Hartmann & Kenyon 1996 review: http://adsabs.harvard.edu/abs/1996ARA%26A..34..207H
* Scholz et al. 2013 systematic survey: http://adsabs.harvard.edu/cgi-bin/bib_query?arXiv:1301.3152
* Clarke et al. 2005 with example lightcurves (Fig. 1): http://adsabs.harvard.edu/abs/2005MNRAS.361..942C

Triggers:YSOecl

2013-07-24T15:08:22Z

Aleks.scholz:

== Eclipsing young stellar objects ==

Characteristics:
* long-lasting eclipses by disk material
* shapes can be irregular
* timescales days to years
* high amplitudes possible (several mags), cutoff of 1mag is probably useful
* very few known, every new detection would help

Trigger is necessary to figure out the origin of the eclipse -- the eclipsing body could be a part of the disk, clumps, protoplanetary structures, etc.

Identification:
* >1mag drop off in magnitude
* red spectrum, any spectral type
* J-K>1. IR excess, UV excess
* IRAC3 [5.8mu] - IRAC4 [8.0mu] > 0.4
* WISE1 [3.5mu] - WISE4 [22mu] > 2.0
* WISE1 [3.5mu] - WISE2 [4.5mu] > 0.3 (weak criterion)
* Halpha emission

Examples:

* KH15D: recurrent, but changing eclipses- see Herbst et al. 2012 http://adsabs.harvard.edu/abs/2010AJ....140.2025H
* RW Aur: singular event - http://figshare.com/articles/A_huge_eclipse_in_the_young_star_RW_Aur/92169
* YLW 16 A: has smaller eclipses- http://adsabs.harvard.edu/abs/2013A%26A...554A.110P

Triggers:YSOecl

2013-07-24T14:32:11Z

Aleks.scholz:

== Eclipsing young stellar objects ==

Characteristics:
* long-lasting eclipses by disk material
* shapes can be irregular
* timescales days to years
* high amplitudes possible (several mags), cutoff of 1mag is probably useful
* very few known, every new detection would help

Trigger is necessary to figure out the origin of the eclipse -- the eclipsing body could be a part of the disk, clumps, protoplanetary structures, etc.

Examples:

* KH15D: recurrent, but changing eclipses- see Herbst et al. 2012 http://adsabs.harvard.edu/abs/2010AJ....140.2025H
* RW Aur: singular event - http://figshare.com/articles/A_huge_eclipse_in_the_young_star_RW_Aur/92169
* YLW 16 A: has smaller eclipses- http://adsabs.harvard.edu/abs/2013A%26A...554A.110P

Triggers:FUOri

2013-07-24T14:30:35Z

Aleks.scholz:

== Eruptive YSOs ==

Prototypes:

FU Oris are an extreme subsample of eruptive classical T Tauri stars. Only one outburst observed, but lasts for decades. Only about a dozen FU Ori bursts observed. V1647 Ori is illuminating a McNeil's nebula in the vicinity of NGC 2068 star-forming region.

[[File:FUOri.png]]
Plot from [http://www.ta3.sk/caosp/Eedition/FullTexts/vol36no3/pp149-157.pdf D.Chochol et al. 2006].

EX Lupis (EXors) have smaller, shorter, recurrent outbursts.

[[File:ExLupi.png|right|400px|thumb|EX Lupi photometry from the ASAS project.]]

OO Ser was discovered in 1994 and is similar to FUors and EXors, but is so deeply embedded, that at its brightest was not visible in J band ([http://ukads.nottingham.ac.uk/abs/1996ApJ...468..861H Hodapp et al. 1996]).
It was observed in infrared with ''Infrared Space Observatory'' and Spitzer ([http://arxiv.org/abs/0705.1231 Kospal et al. 2007]).
It has different time scales than FUors and EXors, is rather a ''fast'' FUor (similar to V1647 Ori) with a time of rise of about 8 months.

Characteristics:

* diverse zoo of lightcurves, use of templates is risky
* many details unknown, unbiased sample required
* rise time varies from months to years
* amplitude range from <1 mag to 5 mag (but 1mag cutoff is probably useful)
* outburst last from months to decades, some are recurrent
* extreme events like FU Ori are very rare
* Spectra: F or G supergiants, red, heavily veiled continuum with strong emission of <math>H_{\alpha}</math>
* At maximum spectral types are in the range Ae(alpha) - Gpe(alpha)
* X-ray variability present
* FU Ori and V1057 Cyg rise over 1 yr, whereas V1515 Cyg rise over 20 years
* FU Ori and V1515 Cyg decline over 20-100 years, V1015 Cyg decays faster (10 yrs)

Trigger is necessary, because immediate follow-up (on timescales of weeks) needed to study the impact of
such accretion bursts on the properties of the dust and gas in the disks. Also, high cadence monitoring
immediately after the event is useful for modeling the source.

References:

* Hartmann & Kenyon 1996 review: http://adsabs.harvard.edu/abs/1996ARA%26A..34..207H
* Scholz et al. 2013 systematic survey: http://adsabs.harvard.edu/cgi-bin/bib_query?arXiv:1301.3152
* Clarke et al. 2005 with example lightcurves (Fig. 1): http://adsabs.harvard.edu/abs/2005MNRAS.361..942C

Triggers:YSOecl

2013-07-19T14:41:59Z

Aleks.scholz:

== Eclipsing young stellar objects ==

Characteristics:
* long-lasting eclipses by disk material
* shapes can be irregular
* timescales days to years
* high amplitudes possible (several mags)
* very few known, every new detection would help

Examples:

* KH15D: recurrent, but changing eclipses- see Herbst et al. 2012 http://adsabs.harvard.edu/abs/2010AJ....140.2025H
* RW Aur: singular event - http://figshare.com/articles/A_huge_eclipse_in_the_young_star_RW_Aur/92169
* YLW 16 A: has smaller eclipses- http://adsabs.harvard.edu/abs/2013A%26A...554A.110P

Triggers:YSOecl

2013-07-19T14:38:41Z

Aleks.scholz: Created page with "== Eclipsing young stellar objects == Characteristics: * long-lasting eclipses by disk material * shapes can be irregular * timescales days to years * high amplitudes possible (..."

== Eclipsing young stellar objects ==

Characteristics:
* long-lasting eclipses by disk material
* shapes can be irregular
* timescales days to years
* high amplitudes possible (several mags)
* very few known, every new detection would help

Examples:

* KH15D recurrent, but changing eclipses- see Herbst et al. 2012 http://adsabs.harvard.edu/abs/2010AJ....140.2025H
* RW Aur singular event - http://figshare.com/articles/A_huge_eclipse_in_the_young_star_RW_Aur/92169
* YLW 16 A has smaller eclipses- http://adsabs.harvard.edu/abs/2013A%26A...554A.110P

Triggers:TTau

2013-07-19T14:21:02Z

Aleks.scholz:

== T Tauri stars ==
[[File:figure_ttau_mag.png|400px|right|thumb|T Cha - example of TTau star from the ASAS data]]

T Tauri type stars are very young (<math> <10^7 </math> y), low mass (<math> <3 M^{}_\odot </math>) pre-main sequence objects [http://adsabs.harvard.edu/abs/1989A%26ARv...1..291A Appenzeller & Mundt 1989].

Characteristics:
* irregular and quasi-periodic variations
* high amplitude (up to 5 mag)
* may have a phase of quiescence (see figure)
* absolute magnitude range: M_V=? to ? mag
* typically do not require a trigger, but watch list of T Tauris would be useful

Triggers

2013-07-19T14:20:19Z

Aleks.scholz:

''' Please expand this section with your favourite types of possible alerts. The most useful information would be the number statistics, amplitude and timescale, example light curve, spectrum and the reasoning for an rapid alert.'''

===Possible triggers for Science Alerts===

* [[Triggers:Asteroids | Asteroids]]

* [[Triggers:Be | Be-type stars]]

* [[Triggers:CVs | Cataclysmic Variables (CVs)]]

* [[Triggers:CNe | Classical novae]]

* [[Triggers:DNe | Dwarf novae]]

* [[Triggers:FUOri | Eruptive young stellar objects]]

* [[Triggers:YSOecl | Eclipsing young stellar objects]]

* [[Triggers:GRBs | Gamma Ray Bursts Optical Counterparts]]

* [[Triggers:LensedSNe | Gravitationally lensed supernovae]]

* [[Triggers:LBVs | Luminous Blue Variables]]

* [[Triggers:Flares | M-dwarf flares]]

* [[Triggers:Microlensing | Microlensing events]]

* [[Triggers:RCrB | R Coronae Borealis type variables (dimming objects)]]

* [[Triggers:Supernovae | Supernovae]]

* [[Triggers:TTau | T Tauri type pre-main sequence stars]]

* [[Triggers:XBs | X-ray binaries (XBs)]]

* [[Triggers:Other | Other rare transients]]

* [[Triggers:Theoretical | Exotic/theoretical events]]

== Table of transients ==
This table is based on [http://arxiv.org/abs/0906.5355 Rau et al. 2009] on Palomar Transient Factory (PTF).
MR is an absolute magnitude in R, tau is time of a decline by 2 mag.
Note, these are not all the types of transites Gaia will detect.

{| border="1" cellspacing="0" cellpadding="5" align="center"
! Class
! MR
! tau
! Universal rate
! Gaia rate
|-
| Dwarf Novae
| 9..4
| 3..20
| <math>3\times10^{-5} \textrm{pc}^{-3} \textrm{yr}^{-1}</math>
|
|-
|Classical Novae
| -5..-10
|2..100
|<math>2\times10^{-10} \textrm{yr}^{-1}\textrm{L}_{\odot,K}^{-1}</math>
|
|-
|Luminous Red Novae
| -10..-14
|20..60
|<math>1.5\times10^{-13} \textrm{yr}^{-1}\textrm{L}_{\odot,K}^{-1}</math>
|
|-
|Fallback SNe
| -4..-21
|0.5..2
|<math>10^{-13} \textrm{yr}^{-1}\textrm{L}_{\odot,K}^{-1}</math>
|
|-
|Macronovae
| -13..-15
|0.3..3
|<math>10^{-4..-8} \textrm{Mpc}^{-3} \textrm{yr}^{-1}</math>
|
|-
|SN .Ia
| -15..-17
|2..5
|<math>(4..10)\times 10^{-6} \textrm{Mpc}^{-3} \textrm{yr}^{-1}</math>
|
|-
|SNe Ia
| -17..-19.5
|30..70
|<math>3\times 10^{-5} \textrm{Mpc}^{-3} \textrm{yr}^{-1}</math>
|
|-
|Tidal disruption flares
| -15..-19
|30..350
|<math>10^{-6} \textrm{Mpc}^{-3} \textrm{yr}^{-1}</math>
|
|-
|Core-collapse SNe
| -14..-21
|20..300
|<math>5\times 10^{-5} \textrm{Mpc}^{-3} \textrm{yr}^{-1}</math>
|
|-
|Luminous SNe
| -19..-23
|50..400
|<math>10^{-7} \textrm{Mpc}^{-3} \textrm{yr}^{-1}</math>
|
|-
|Orphan afterglows (SGRB)
| -14..-18
|5..15
|<math>3\times 10^{-7..-9} \textrm{Mpc}^{-3} \textrm{yr}^{-1}</math>
|
|-
|Orphan afterglows (LGRB)
| -22..-26
|2..15
|<math>3\times 10^{-7..-9} \textrm{Mpc}^{-3} \textrm{yr}^{-1}</math>
|
|-
|On-axis LGRB afterglows
| ..-37
|1..15
|<math>4\times 10^{-10} \textrm{Mpc}^{-3} \textrm{yr}^{-1}</math>
|
|-
|}

----
== CMD of selected variables and transients ==
CMD paths of various types of variable stars, including Be stars, R CrB and V4334 Sgr. From [http://arxiv.org/abs/0907.4090 Spano et al. 2009]

[[File:VariablesPathsCMDLMC.png|650px]]

----
== Time scales and amplitudes ==
[[File:Kulkarni-absmag-timescale.png|400px|left|thumb|Absolute magnitude vs timescale of novae, supernovae and some of new transients. From Kulkarni (2009).]]

[[File:plot_transients_tau_ampl.png|400px]]
[[File:plot_transients_trise_ampl.png|400px]]
[[File:plot_transients_tdecline_ampl.png|400px]]
[[File:plot_transients_trise_tdecline.png|400px]]

Triggers:FUOri

2013-07-19T14:18:14Z

Aleks.scholz:

== Eruptive YSOs ==

Prototypes:

FU Oris are an extreme subsample of eruptive classical T Tauri stars. Only one outburst observed, but lasts for decades. Only about a dozen FU Ori bursts observed. V1647 Ori is illuminating a McNeil's nebula in the vicinity of NGC 2068 star-forming region.

[[File:FUOri.png]]
Plot from [http://www.ta3.sk/caosp/Eedition/FullTexts/vol36no3/pp149-157.pdf D.Chochol et al. 2006].

EX Lupis (EXors) have smaller, shorter, recurrent outbursts.

[[File:ExLupi.png|right|400px|thumb|EX Lupi photometry from the ASAS project.]]

OO Ser was discovered in 1994 and is similar to FUors and EXors, but is so deeply embedded, that at its brightest was not visible in J band ([http://ukads.nottingham.ac.uk/abs/1996ApJ...468..861H Hodapp et al. 1996]).
It was observed in infrared with ''Infrared Space Observatory'' and Spitzer ([http://arxiv.org/abs/0705.1231 Kospal et al. 2007]).
It has different time scales than FUors and EXors, is rather a ''fast'' FUor (similar to V1647 Ori) with a time of rise of about 8 months.

Characteristics:

* diverse zoo of lightcurves, use of templates is risky
* many details unknown, unbiased sample required
* rise time varies from months to years
* amplitude range from <1 mag to 5 mag
* outburst last from months to decades, some are recurrent
* extreme events like FU Ori are very rare
* Spectra: F or G supergiants
* Spectrum: red, heavily veiled continuum with strong emission of <math>H_{\alpha}</math>; in blue consistent with an early B spectral type
* At maximum spectral types are in the range Ae(alpha) - Gpe(alpha)
* X-ray variability present
* FU Ori and V1057 Cyg rise over 1 yr, whereas V1515 Cyg rise over 20 years
* FU Ori and V1515 Cyg decline over 20-100 years, V1015 Cyg decays faster (10 yrs)

References:

* Hartmann & Kenyon 1996 review: http://adsabs.harvard.edu/abs/1996ARA%26A..34..207H
* Scholz et al. systematic survey: http://adsabs.harvard.edu/cgi-bin/bib_query?arXiv:1301.3152

Triggers:FUOri

2013-07-19T14:14:19Z

Aleks.scholz:

== Eruptive YSOs ==

Prototypes:

FU Oris are an extreme subsample of eruptive classical T Tauri stars. Only one outburst observed, but lasts for decades. Only about a dozen FU Ori bursts observed. FU Ori itself (V1647 Ori) is illuminating a McNeil's nebula in the vicinity of NGC 2068 star-forming region.

[[File:FUOri.png]]
Plot from [http://www.ta3.sk/caosp/Eedition/FullTexts/vol36no3/pp149-157.pdf D.Chochol et al. 2006].

EX Lupis (EXors) have smaller, shorter, recurrent outbursts

[[File:ExLupi.png|right|400px|thumb|EX Lupi photometry from the ASAS project.]]

OO Ser was discovered in 1994 and is similar to FUors and EXors, but is so deeply embedded, that at its brightest was not visible in J band ([http://ukads.nottingham.ac.uk/abs/1996ApJ...468..861H Hodapp et al. 1996]).
It was observed in infrared with ''Infrared Space Observatory'' and Spitzer ([http://arxiv.org/abs/0705.1231 Kospal et al. 2007]).
It has different time scales than FUors and EXors, is rather a ''fast'' FUor (similar to V1647 Ori) with a time of rise of about 8 months.

Characteristics:

* diverse zoo of lightcurves
* many details unknown, unbiased sample required
* rise time varies from months to years
* amplitude range from <1 mag to 5 mag
* outburst last from months to decades
* extreme events like FU Ori are very rare
* Spectra: F or G supergiants
* Spectrum: red, heavily veiled continuum with strong emission of <math>H_{\alpha}</math>; in blue consistent with an early B spectral type
* At maximum spectral types are in the range Ae(alpha) - Gpe(alpha)
* X-ray variability present
* FU Ori and V1057 Cyg rise over 1 yr, whereas V1515 Cyg rise over 20 years
* FU Ori and V1515 Cyg decline over 20-100 years, V1015 Cyg decays faster (10 yrs)

References:

* Hartmann & Kenyon 1996 review: http://adsabs.harvard.edu/abs/1996ARA%26A..34..207H
* Scholz et al. systematic survey: http://adsabs.harvard.edu/cgi-bin/bib_query?arXiv:1301.3152