GCN Circulars
GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.
Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
- IPN triangulation of GRB031130 (large error box)
- GRB031111A, prompt optical observations
- GRB 030329: Planned XMM-Newton Observation
- IPN triangulation of GRB031120 (two large error boxes)
- GRB 031111B (= H2925) : Kyoto Optical Observation
- IPN/HETE localization of GRB031109 (=H2917; large error box)
- IPN detection of activity from SGR1806-20
- GRB 031111, Radio observations
- IPN triangulation of GRB031114 (large error box)
- IPN triangulation of GRB031107 (two large error boxes)
- GRB 031111: Optical observations
- GRB 031111, optical observations
- SN 2003jd (SN/GRB?) -- X-ray Observations
- HETE Prompt GRB Spectral Analyses
- IPN triangulation of GRB031111 (=H2924): small error box
- XRF031109 (=H2919): A very long XRF localized by HETE
- IPN triangulation of GRB031108 (large error box)
- GRB031026: 1.2mm upper limit with MAMBO at the IRAM 30m
- GRB030929/SN2003jd association unlikely based on IPN localiztion
- IPN triangulation of GRB031027 (small error box)
- IPN triangulation of GRB031026B (large error box)
- Lulin optical follow-up observations of GRB031026
- SN 2003jd (SN/GRB?), Radio Observations
- SN 2003jd (SN/GRB?) - possible association with GRB 030929
- GRB 031026: Further Ic Observations
- GRB 031026 (=H2882): Evidence for High Redshift from Prompt
- Peculiar Type Ic SN 2003jd (SN/GRB?), optical spectrum
- IPN triangulation of GRB031024 (single error box)
- GRB031026 (=H2882): A Long, Hard Spectrum Burst Localized by HETE
- GRB 031026: Ic Observations
- GRB031026 : KISO optical follow-up observation
- IPN triangulation of GRB031024 (annulus)
- IPN triangulation of GRB031020 (large error box)
- GRB030329: radio observations at RT-22 (CrAO)
- IPN triangulation of GRB031016 (two large error boxes)
- IBAS alert 1180 refers to a burst from SGR 1806-20
- HETE Prompt GRB Light Curves and Color-Color Diagrams
- IPN triangulation of GRB031014 (annulus)
- Ongoing Bursting Activity from SGR 1806-20 detected with IBAS
- XRF 030824: additional observations at CFHT
- SGR1806-20 bursts on 031008. Helicon detection and small error box.
- IPN triangulation of GRB031008 (annulus)
- SGR 1806-20 bursts with INTEGRAL and IBAS announcement on Soft Gamma-Ray Repeaters
- IPN detection of continued activity from SGR1806-20
- IPN triangulation of GRB031007 (two large error boxes)
- XRF 030723: Subaru Optical Observations
- IPN triangulation of GRB031004B (annulus)
- IPN triangulation of GRB031004A (short/hard; annulus)
- IPN triangulation of GRB030929 (short/hard; annulus)
- A burst from SGR 1806-20 detected with IBAS
- XRF 030824: Early follow-up observation at Kiso observatory
- XRF 030824: observations at CFHT
- IPN triangulation of GRB030926 (short/hard; large error box)
- IPN triangulation of GRB030922B (large error box)
- XRF 030723: Detection of the likely host galaxy
- XRF030824 (=H2821): An X-Ray Flash Localized by the HETE WXM
- XRF030823 (=H2818): An X-Ray Flash Localized by the HETE WXM and SXC
- IPN triangulation of GRB030922A (large error box)
- IPN triangulation of GRB030921 (large error box)
- IPN triangulation of GRB030919 (large error box)
- GRB030922 triangulation (annulus)
- GRB030913: Subaru Optical Observations
- GRB 030913: ROTSE-3c Optical Observations
- GRB030913: OT's limit by MASTER
- GRB030921 triangulation (annulus)
- GRB030913, candidate afterglow observations
- GRB 030913, optical candidate
- GRB030913: AAVSO optical observations
- GRB 030913, BOOTES observations
- GRB030913 (=H2849): Confirmation of the Flight Localization
- IPN triangulation of GRB030916 (possible short/hard GRB; large error box)
- GRB030913 (=H2849): TAROT Observations
- GRB030913: wide field imaging (7 sq.deg) of the error box by MASTER
- Magellan Observations of GRB030725 (=H2779)
- GRB030913 (=H2849): A GRB Possibly Localized by HETE
- IPN triangulation of GRB030908 (annulus)
- GRB 030913: Optical limit at RIKEN
- XRF 020427: Gemini-South Spectroscopic Observations of the Host
- XRF030824: Optical observations
- IPN triangulation of GRB030903 (large error box)
- IBAS detection of bursts from SGR 1806-20
- Radio Observations of SGR1806-20
- IPN triangulation of GRB030831 (annulus)
- IPN triangulation of GRB030830 (large error box)
- GRB 030824: Candidate Follow-Up
- INTEGRAL ToO OBSERVATIONS OF SGR1806-20: CALL FOR CORRELATED OBSERVATIONS
- IPN triangulation of GRB030827 (large error box)
- GRB 030823 observation at Ouda
- XRF030824: Second-epoch Palomar observations
- XRF030824: optical observations
- IPN triangulation of GRB030822 (annulus)
- GRB030823: optical observations
- GRB030823: Palomar observations
- XRF030824: Palomar observations
- GRB 030824: Candidate Afterglow (or Variable/Flare Star?)
- GRB030823: optical observation at Tokyo Tech
- RAPTOR observations of GRB030823
- Lulin follow-up observations of GRB030823
- IPN triangulation of GRB030821 (=H2814; refined error box)
- GRB 030821(=H2814): A Faint, Long GRB Localized by the HETE WXM and the IPN