Summary

A number of ground- and space-based projects benefit from the help of amateur observers in coordination with professionals. Among them, alert-based observation is particularly well suited, and the Gaia mission is one of the most emblematic examples. This mission issues quasi-daily alerts for the detection of transient events: potentially new asteroids (until the end of 2023, Gaia-FUN-SSO), unknown stellar or extragalactic sources with strong photometric variations. A mainly professional community responds to scientific alerts (https://gsaweb.ast.cam.ac.uk/alerts/alertsindex). In addition, alerts are multiplying following the deployment of numerous ground-based robotic telescopes (ZTF, ASSAS-SN, ATLAS, etc.), which require validation and also classification. Amateurs can make an important contribution to the response to these numerous alerts. Our RAPAS (Reseau Amateurs Professionnels pour les Alertes Scientifiques) project aims to reinforce and coordinate the response to these alerts by setting up a network of observers in France to enable rapid validation of detections and their photometric follow-up.

In 2022 we studied and produced a set of 25 filter sets harmonized with the Gaia photometric system, now deployed in the network of observers enrolled in the network. In 2023 we quantified the quality and homogeneity of the methods and photometric measurements reduced in the Gaia system. We have also initiated the process of network response to alerts. Work has now begun on the second aspect of the project: spectral characterization of the optical signature of an alert event. Two prototype spectrometers have been acquired and are currently being tested. In 2024, we are extending the number of network participants and producing and distributing a new batch of filters.

Preliminary scientific program

RAPAS Workshop December 14-15, 2024
preliminary program
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NB: At this date, speakers are prospective only.
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1. Introduction (Th. Midavaine, W. Thuillot, M. Dennefeld, Ch. Buil)

2. Solar system object alerts

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Near-Earth objects: objectives, current status, Gaia’s contribution (W. Thuillot, P. Tanga, D. Hestroffer)
Tools for NEA astrometry: Tycho tracker (A. Maury, Ph Dupouy,...), Prism, GBOT (S. Bouquillon)

3. Alert broadcasters

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BHTOM (L. Wyrzykowski)
AstroColibri (F. Schusler)
Super Novae (M. Dennefeld)
ProAm UAI activity: Transient Name Server(M. Dennefeld)

4. Filters

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Distribution and network status (Th. Midavaine)
Calibration vs Gaia (M. Serrau, F. Losse, Th. Midavaine)
2nd generation filters (Th. Midavaine, M. Flury)

5. Photometric reduction and detection of optical candidates on alerts

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tools: Prism (Marc Serrau), Muniwin (A. Wunshe), AstroImageJ (Florent Losse), Siril (Lisa Maris), Python (Pier Francesco Rossi)

6. Spectroscopes

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Status of 2 spectroscopes: Alpy and Star’Ex (Ch. Buil, Th. Midavaine)
Feedback on the Alpy 200 with a C11 (Robin Leadbeater)
Review of TJMS tests (Michael Irzyc, Jean Michel Vienney), SAT (...), Les Pises (Jean Marie Lopez)
Proposed iterations and finalization of the definition of the Alpy 200 and Star’Ex VLR

7. Feedback

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Photometry, spectroscopy (all observers)

8. Discussion

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Projects for RAPAS 2025