using PS1 (following an ad hoc lunch discussion with Zeljko). Is there something new to be done?
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| from Richard Anderson's (2013) thesis |
What is known? Literature points towards a catalog by Berdnikov et al (2000,
http://adsabs.harvard.edu/abs/2000A%26AS..143..211B) with 500 Cepheids in the Galaxy. [Note: M31 has about 1500-2000 known Cepheids: http://arxiv.org/pdf/1301.6170v1.pdf]
Reading that Berdnikov paper, I could not gleam anything about the "election function" that led to this catalog. The recent thesis by Richard Anderson (Geneva, 2013) has a nice summary.
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This is the distribution of the "known" Galactic Cepheids in apparent mean Bmag vs P[days]
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| Who knows what selection function led to this distribution in the X - Y (kpc) spatial distribution... Is that dust?. |
For periods of 5 days, their absolute V-band magnitude (presumably de-reddened) should be -3.4.
This means at a distance of 5 kpc, they should be "easy" for PS1 at <m_g>=18 for 8 mag of visual extinction....
Things to do:
- look at the light curves of known Cepheids in PS1
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| from Richard Anderson's thesis |
Peter Yoachim has devised a set of (multi-color) template light curves.
- look at the (bizarre) Wesenheit reddening-free abs. mags. Questions: e.g. at what phase (phase-averaged?) are those corrective colors calculated.?
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| Anderson (2013) thesis |
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| This dereddened magnitude W leads to a far better PLR. |
- see how Cepheids show up in a structure-function plot
Input from Laurent Eyer (who is one of the variability Gurus for Gaia), who wrote on that
topic earlier (in a slightly obscure place):
Gaia should be able to detect 9000 Cepheids; I see few reasons that Gaia can identify many
Cepheids that PS1 can find; so, the potential for 5000 new Galactic disk Cepheids from PS1 compared to 500 in the "state of the art catalog" now?!?
Here's the communication with Laurent [this site does not accept pdf's with a permalink]:
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