article on degeneracies

[rpoleski]

It would be good to add article on degeneracies in microlensing model fitting. Below is a list that I came up with, but not exclusive. Note that some of these effects will not apply to WFIRST because they arise due to not enough data.

• blending and PSPL: Wozniak & Paczynski 1997
• wide/close: Dominik 1999
• jerk parallax: Gould 2004 and Park+2004
• parallax vs. orbital motion: Gaudi+08, Batista+11, and Skowron+11
• satellite parallax: Refsdal 1966 and Gould 1994
• in planetery caustics: Gaudi & Gould 1997 and Calchi Novati+18 - this is also called "inner/outer degeneracy"
• planet vs. equal-mass binary: Choi+12
• binary with orbital motion vs. triple lens: Bennett+99, Jung+13, and Han+16
• rho degeneracy: Chung+17
• wide degeneracy: Bennett+12 and Sumi+16
• binary source vs. planetary lens producing long-term anomaly Jung+17
• s vs. 1/s for planetary caustics: Bhattacharya+16 and Poleski+18
• see also Song, Mao & An 2014, Lee 2017

[rpoleski]

One more:

• binary lens with small caustic and the source larger or smaller than the caustic: Hwang+18

[rpoleski]

The very obvious one:

• parallax vs. xallarap

[rpoleski]

• inside/outside degeneracy for minor image perturbation Han+18

[rpoleski]

The sooner somebody writes this article, the sooner I'll stop posting here.

• binary-lens vs binary-source for high magnification events: Calchi Novati+18, Suzuki+18
• 3 different families of binary lens models for double-peaked high-mag event: Dominik+18
• positive/negative u_0 but pi_E is the same: Dominik+18

[rpoleski]

• PSPL with different t_E - I think it's not covered above - see sub-sub-section Parameter recovery in Mróz+17

@gbryden, do you like this issue?

[rpoleski]

• continuous (circular) degeneracy in parallax for events with good ground-based coverage and poor satellite coverage Gould 2019

@cbhender - are you turning these notes into an article?

[cbhender]

Hi Radek,

I have not yet begun turning this into an article, but I could if there is a push for this being a high priority, whether from the MicroSIT or just generally.

Tally ho,

Calen

On Wed, May 29, 2019 at 1:41 PM Radek Poleski notifications@github.com wrote:

• continuous (circular) degeneracy in parallax for events with good ground-based coverage and poor satellite coverage Gould 2019 https://arxiv.org/abs/1905.06770

@cbhender https://github.com/cbhender - are you turning these notes into an article?

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[rpoleski]

I strongly recommend putting this in a more formal thing if you can. This thing could be microlensing-source post/article or an arxiv posting. Just look how long this list is and the cases when even very experience modellers have published papers without checking all degenerate solutions.

I can help, but I don't have a good idea how this should be done : (

[cbhender]

I've thought about it a bit, and I think one avenue to go would be to create an Overleaf LaTeX document with an accompanying Jupyter notebook that shows, e.g., caustics+source trajectories and light curves. This could then be posted to astroph at some point when our list is complete (or mostly complete?)

-Calen

On Thu, May 30, 2019 at 7:10 PM Radek Poleski notifications@github.com wrote:

I strongly recommend putting this in a more formal thing if you can. This thing could be microlensing-source post/article or an arxiv posting. Just look how long this list is and the cases when even very experience modellers have published papers without checking all degenerate solutions.

I can help, but I don't have a good idea how this should be done : (

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[rachel3834]

I would absolutely encourage you to turn this article into a review paper and post it to the archive, as well as incorporating it as an article for microlensing-source. We can embed some interactivity (i.e. from the notebook) into the website.

On Mon, Jun 3, 2019 at 11:22 AM cbhender notifications@github.com wrote:

I've thought about it a bit, and I think one avenue to go would be to create an Overleaf LaTeX document with an accompanying Jupyter notebook that shows, e.g., caustics+source trajectories and light curves. This could then be posted to astroph at some point when our list is complete (or mostly complete?)

-Calen

On Thu, May 30, 2019 at 7:10 PM Radek Poleski notifications@github.com wrote:

I strongly recommend putting this in a more formal thing if you can. This thing could be microlensing-source post/article or an arxiv posting. Just look how long this list is and the cases when even very experience modellers have published papers without checking all degenerate solutions.

I can help, but I don't have a good idea how this should be done : (

— You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub < https://github.com/rachel3834/microlensing-online/issues/14?email_source=notifications&email_token=AKEU7AI4LYI6RIU4NF543MDPYCCK7A5CNFSM4EP3BUBKYY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGODWT77UQ#issuecomment-497549266 , or mute the thread < https://github.com/notifications/unsubscribe-auth/AKEU7ALBK3FYJBH3OCBFFNLPYCCK7ANCNFSM4EP3BUBA

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[rpoleski]

• rho degeneracy in poorly-covered central-caustic anomaly event: Han+20 - maybe this falls in some previous one?

[rpoleski]

Somehow I've omitted this one:

• planet vs binary source Gaudi 1998

[rpoleski]

• t_star for binary lenses: Bennett+14

[rpoleski]

• paper by Johnson+21 - single lens and extreme finite source

[rpoleski]

• triple lens: planet in a binary vs. multi-planet - Han+19

[rpoleski]

• caustic-chiral degeneracy - Skowron+18, this accidental and the name was given by Han+19; I'm not sure it it wasn't reported before
• finite/point-source degeneracy Han+19, but it seems the same was shown by Poleski+17 and maybe some other papers before; accidental

[rpoleski]

• "A ubiquitous unifying degeneracy in two-body microlensing systems" Zhang, Gaudi & Bloom 2022