Proposer's Guidance
EINSTEIN PROBE MISSION CALL FOR OBSERVING PROPOSALS
-- 1st Cycle
Proposal Submission Deadline:
Wednesday, December 20th 2023, 6:00 PM UTC+8 (Beijing)
Letter of Invitation from EP Science Center for Cycle-1 (pdf)
Einstein Probe (EP) is an upcoming astronomical space mission led by the Chinese Academy of Sciences (CAS) and developed in collaboration with the European Space Agency (ESA), the Max Planck Institute for extraterrestrial Physics (MPE), and the French Space Agency (CNES). The primary goals of EP are to discover high-energy transients and monitor variable objects in the soft X-ray band, and to characterize them with quick X-ray follow-up observations.
To achieve this, EP employs a large instantaneous field-of-view of 3600 deg2 with its 12 identical modules of lobster-eye Wide-field X-ray Telescopes (WXTs). WXT has a moderate angular resolution of FWHM ~ 5 arcmin and positioning accuracy of 1 arcmin (90%) in the 0.5 - 4 keV energy band. EP also has the capability of performing fast and deep follow-up observations in the 0.3 - 10 keV energy band with its two units of Follow-up X-ray Telescopes (FXTs). The total effective area is about 2 x 300 cm2 @ 1 keV. The angular resolution is HPD ≤ 30 arcsec, and the positioning accuracy is 8.6 arcsec (90%). The EP satellite can conduct quick downlink of transient alert messages, as well as quick uplink of urgent Target-of-Opportunity (ToO) observation commands. The satellite will operate in a low-Earth orbit with a period of 97 minutes. Please refer to the “EP Technical Handbook” for more details.
This is an announcement for EP observing proposals during the first year of EP scientific operations (Cycle-1).
The EP launch is currently scheduled at the end of 2023. Once in orbit EP will conduct a series of tests, performance verification and instrument calibration during the first 6 months, after which scientific operations will be started.
The science operational time is composed of two parts, the Regular Operational Time (ROT) and Targets of Opportunity (ToO). The ROT observations further comprise Survey Mode observations with WXT and Follow-up observation with FXT. The WXT survey is the basic operational mode of EP designed to monitor the sky to detect transients and monitor variable sources. EP will operate in this mode unless a follow-up observation or ToO observation is triggered. During the survey mode, WXT will monitor pre-planned sky regions, whilst FXT will be normally pointed to pre-selected targets to perform pointed observations, termed FXT Survey Target Observations (FSTO). ToO observations comprise two kinds, regular ToOs requested when observing opportunities arise any time during EP operations and pre-approved anticipated observations of known targes (anticipated-ToO). FSTO and anticipated-ToO targets are based on projects proposed by the EP Science Topical Panels (STPs) and guest observers, endorsed by the EP Science Management Committee (SMC).
2.1 Who can propose:
For this first Cycle, only the following two types of prospective EP users can submit observing proposals as principal investigator (PI).
1) STP observer: EP STP members and associate members.
2) Guest observer (GO): non-STP users whose primary affiliations are Chinese institutions (including Hongkong, Macao and Taiwan).
2.2 Types of proposals available for Cycle-1:
There are two types of observing proposals available in Cycle-1.
1) FSTO observations (non-ToO observations) performed by using FXT.
2) Anticipated-ToO for known X-ray sources, including observations of known sources triggered by external facilities or EP-WXT (triggered onboard or on-ground). For WXT triggering, the proposed threshold should be at or above the detection limit for one typical survey pointing (~1 ks), which is about (2-3)×10-11 erg cm-2 s-1.
2.3 Properties of Cycle-1 proposals:
2.4 What are not included in Cycle-1:
2.5 Summary table of types of proposals:
Type of Proposals |
Included in Cycle-1? |
Proposers in Cycle-1 |
Allowed Targets in Cycle-1 |
Type of Programs |
FSTO |
yes |
STP observers, Guest observers* |
known sources |
single obs, monitoring, tilling |
Anticipated-ToO |
yes |
known X-ray sources |
||
*Primary affiliations are Chinese institutions (including Hongkong, Macao and Taiwan). See the text above for detailed explanations and constraints. |
All proposers are advised to read the following content carefully. Only complete and successfully submitted proposals will receive full consideration.
Please note that the proposal process for ESA, MPE and CNES may differ in parts from the described approach below. Additional information will be provided within each Party by the representatives.
3.1 User registration:
Every proposer should first create a user account on the EP website (https://ep.bao.ac.cn/ep/user/login). Please register with your real personal information such as name, email address and affiliation. After the approval of system administrator, you may log into the EP website and access the EP Observing Proposal System (EOPS). Your role in the EP science team will be recognized automatically. Proposers with different roles will be directed to different proposal submission interfaces.
3.2 Proposal submission:
The deadline for EP Cycle-1 proposal submission is Wednesday, December 20th 2023, 6:00 PM UTC+8 (Beijing).
All EP observing proposals must be submitted via EOPS. After logging into the system, you may start creating new proposals, filling out online forms and uploading scientific justification file. Only complete proposals can be submitted (see the required items below).
There will be a countdown clock on EOPS. The submission button will be invalid after the deadline. It is possible that the system may be overloaded and react slowly close to the deadline. Thus to avoid last-minute problems, please get familiar with EOPS early, prepare and submit your proposals early.
3.3 Required items for a complete proposal:
All complete proposals submitted to Cycle-1 should consist and only consist of the following items.
The current launch date of EP is the end of 2023. Once operating in orbit, EP will first perform a series of instrumental tests, calibration and performance-verification (PV) observations, which may last approximately six months. After that, the approved Cycle-1 programs will start to be scheduled and conducted. The default duration of Cycle-1 observing period is one year.
Formal Announcement of Cycle-1 |
October 16th 2023 |
Proposal Submission Due Date |
December 20th 2023 |
Announcement of SMC-Approved Programs |
Approx. March 2024 |
Start of Cycle-1 Observations |
Approx. June 2024 |
The following documents can be downloaded from the Cycle-1 website.
The proposal must not exceed 4 pages and must be submitted as a PDF file. Proposers are urged to use the Latex template or MS word template provided above. A PDF file can be generated from the Latex file with the following command:
> pdflatex ep_scijust_template.tex
A font size of 12pt and a single-column format is strongly recommended. The 4-page limit includes all materials, i.e. texts, figures, tables and references. Proposers must make sure that the PDF generated is complete both when displayed with a viewer and when printed on paper.
This document includes more detailed technical information about the EP mission, instruments and operation.
Link: https://ep.bao.ac.cn/ep/proposal_submit/target_visibility_tool
Link: https://ep.bao.ac.cn/ep/simulator
Link: http://epfxt.ihep.ac.cn/simulation/obs_sim
Link: http://epfxt.ihep.ac.cn/simulation/filter_mode_eval
Link: http://epfxt.ihep.ac.cn/simulation/expo_time_est
[1] The short-tearm visibility check tool will be put online after the launch of EP.