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Call for Proposals for the East Asian VLBI Network (EAVN) for the 2023B semester Proposal submission deadline: 2023 June 1 (Thu.), 8:00 UT EAVN website: https://eavn.kasi.re.kr/

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--- Major revisions from the 2023A semester ---

* Nobeyama, Kunming, and KVN Tamna do not join the open-use program in the 2023B semester. (See Section 1)

* 1-beam hybrid mode is not operated in the 2023B semester. (See Section 2)

* EAVN accepts a proposal which requests observations across two successive semesters. (See Section 4)

* In the 2023B semester, proposers are asked to submit a proposal via e-mail. (See Section 6)

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*** 1. Overview ***

We invite proposals for open-use observations with the East Asian VLBI Network (EAVN), which is the international collaborative VLBI array between China, Korea, and Japan. In the 2023B semester, 13 telescopes (KaVA (VERA 4 x 20 m and KVN 2 x 21 m), Tianma 65 m, Sheshan 25 m, Nanshan 26 m, Takahagi 32 m, Hitachi 32 m, Yamaguchi 32 m, and Sejong 22 m) participate in the EAVN open-use program. Note that three partner telescopes of EAVN, Nobeyama 45 m, Kunming 40 m, and KVN Tamna 21 m, do not join the open-use program in the 2023B semester.

*** 2. Observing mode ***

EAVN provides opportunities of VLBI observations with a data recording rate of 1 Gbps (total bandwidth of 256 MHz) and with single polarization at 6.7, 22, and 43 GHz. Dual-polarization mode is also opened as a shared-risk operation with the maximum of 8 telescopes (KaVA 6 telescopes + any of Tianma, Nanshan, and Takahagi). Dual-frequency (22 and 43 GHz) simultaneous observation system can also be used for EAVN observations at KaVA and Sejong, while the observing term in which the system is available will be determined later. Note that only the single-polarization mode is operational for dual-frequency simultaneous observation. Details of available observing mode can be found in the EAVN Status Report on the EAVN website. Note that 1-beam hybrid mode is not operated in the 2023B semester.

*** 3. Telescope time and array configuration *** The total available observation time for EAVN is up to 500 hours in the 2023B semester, while the available observing time for individual EAVN telescopes are different. Please refer to the EAVN status report on the EAVN website for more details. All EAVN observations will be allocated between 2023 September 1 and 2024 January 15.

EAVN accepts a request for usage of sub-array configuration (KaVA 6 telescopes and additional telescopes from non-KaVA stations). There are several conditions of the antenna combination depending on the observing frequency. Further details about the sub-array configuration are shown in the EAVN status report.

*** 4. Maximum total request time ***

In the 2023B semester, no limitation of the maximum request time for a single proposal is determined in case of usage of only KaVA 6 stations, while one can request for the maximum total telescope time of 50 hours for Tianma and Nanshan, 36 hours for Takahagi, Hitachi, and Yamaguchi, and 24 hours for Sejong.

EAVN accepts a proposal which requests observations across two successive semesters (2023B (2023 September 1 – 2024 January 15) and 2024A (2024 January 16 – June 15)). In this case, one can request for the maximum total telescope time of 100 hours for Tianma and Nanshan, 72 hours for Takahagi, Hitachi, and Yamaguchi, and 48 hours for Sejong.

*** 5. Target of opportunity ***

EAVN accepts target of opportunity (ToO) proposals. Note that Sejong cannot be included for ToO proposals. It is strongly recommended that ToO proposals (especially expected ToO) are submitted during the regular CfP, while unexpected or urgent ToO can be submitted as Director's Discretionary Time (DDT) proposals at any time. Note that the total approved time for ToO observation in the 2023B semester is limited to be 100 hours for ToO proposals for both expected and unexpected events.

ToO proposals must address clear triggering criteria to initiate an observation. ToOs are valid for one year after it is approved. ToO proposals for DDT should follow the same way of regular call and should be submitted via the EAVN website.

*** 6. Proposal submission ***

In the 2023B semester, proposers are asked to submit a proposal via e-mail to ‘eavnprop_at_kasi.re.kr’. Two PDF documents for a proposal cover sheet and a body of proposal including scientific and technical justification should be attached on a message. Please send each proposal separately in case of submitting more than one proposal. Proposal submission deadline is 2023 June 1 (Thu.), 8:00 UT. Please refer to the EAVN status report for detailed information about the proposal format. The designated cover sheet form can be downloaded from the EAVN website.

*** 7. Acknowledgment ***

All EAVN users are asked to specify the acknowledgment to EAVN in their publications. A template for the acknowledgment can be found in the EAVN website.

Sincerely,

Mareki Honma

Director of Mizusawa VLBI Observatory, NAOJ

Kee-Tae Kim

Director of Radio Astronomy Division, KASI

Zhi-Qiang Shen

Director of Shanghai Astronomical Observatory, CAS

and

Na Wang

Director of Xinjiang Astronomical Observatory, CAS

Zhi-Qiang Shen

Director of Shanghai Astronomical Observatory, CAS

and

Na Wang

Director of Xinjiang Astronomical Observatory, CAS