Skip to main content
New! Browse Circulars by Event, Advanced Search, Sample Codes, Schema Release. See news and announcements

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').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"
  1. XRF/GRB 011030: Detection of the Probable Host Galaxy
  2. GRB 020305: Candidate optical afterglow
  3. Type Ic SN2002bl (SN/GRB?) Radio Observations
  4. GRB020305, optical observations
  5. GRB020305: Optical Observations
  6. IPN triangulation of GRB020305 (HETE 1939)
  7. GRB020305 (=H1939): Localization of a GRB by HETE
  8. GRB 020305: Optical observations
  9. HST Imaging of the afterglow and host of GRB 011121
  10. GRB 010921: HST Observations
  11. IPN detection and localization of Cygnus X-1 flares
  12. GRB020127: Further VLA Observations of Possible Counterparts
  13. RXTE Observations of SGR 1900+14
  14. IPN detection of further SGR1900+14 activity
  15. SGR1900+14 activity
  16. IPN/HETE Detection of Bursts from SGR1900+14
  17. IPN Upper Limits to a GRB Associated With SN2002ap
  18. GRB020124 BVRI field photometry
  19. GRB020127: Palomar and VLA Observations of Possible Counterparts
  20. GRB020127: Comparison of Chandra Epochs and Identification of Possible Counterparts
  21. SN2002ap (SN/GRB?) Echelle spectra
  22. SN2002ap (SN/GRB?) optical spectrographic observations
  23. GRB020127, WSRT radio observations
  24. GRB020127 Optical Observations
  25. SN 2002ap (SN/GRB?)
  26. SN 2002ap in M74
  27. SN2002ap (SN/GRB?) UBVRI Field Photometry
  28. GRB020127: Chandra Observations and Prospective Counterparts
  29. pre-SN2002ap (SN/GRB?) imaging of M74
  30. SN 2002ap (hypernova / GRB ??): special list on VSNET
  31. Type Ib/c SN2002ap (SN/GRB?)
  32. Type Ib/c SN2002ap (SN/GRB?) Radio Observations
  33. GRB020124, optical observations
  34. GRB020127: Optical observations
  35. GRB 020127, I-band observations starting 3.14-hr after the event
  36. IPN detection of further activity from SGR1806-20
  37. IPN triangulation of GRB020127 (=H1902)
  38. GRB020127 Optical Observations -- Erratum to GCN 1230
  39. GRB010921 Optical Observations
  40. GRB020127(=H1902): Localization of a Double-Peaked GRB by HETE
  41. GRB020124: Optical observations
  42. VLT observations of GRB 020124: The fading optical/near-infrared afterglow
  43. GRB020124: Optical observations
  44. GRB 020124: Optical observations
  45. GRB 020124 Optical Observations
  46. IPN triangulation of GRB020124 (HETE 1896)
  47. IPN observations of SGR1806-20
  48. GRB 020124: Optical afterglow
  49. GRB020124(=H1896): Localization of a Long GRB by HETE
  50. HETE 1896: Optical observations
  51. GRB optical counterpart candidate in GCN 1217 is M dwarf
  52. Possible optical counterpart to a GRB
  53. GRB011212, Optical Observations
  54. GRB011211: BeppoSAX/GRBM data
  55. Optical polarization observations for GRB011211
  56. GRB 011211: Detection of the Probable Host Galaxy
  57. GRB 011130 and GRB 011212 - Milagro GeV/TeV Observations
  58. Color indices of the afterglow of GRB011211
  59. GRB011212: Optical observations at Gunma
  60. GRB 011211, spectrum and optical photometry
  61. GRB 011130: Optical Observations of X-ray and Radio Sources
  62. GRB 011130, Radio/X-ray Comparison
  63. GRB011212: Optical observations
  64. GRB 011212: optical observation at Asiago
  65. GRB 011211: Evidence for an Optical Break
  66. GRB 011211: TNG Spectroscopic Observations
  67. optical follow-up of GRB(XRF) 011211
  68. GRB 011212: optical observation at Oslo (relayed)
  69. GRB 011211: Optical Spectroscopy
  70. GRB 011211, Optical Observations
  71. GRB011212, BVRI field photometry
  72. GRB011211, BVRI field photometry
  73. GRB011212: Optical observations
  74. GRB 011211: BVRi-band photometry
  75. GRB011212 (=H10001): An X-Ray Rich GRB Detected by HETE
  76. Fading of the optical source associated of XRF 011211
  77. XMM-Newton observation of GRB011211
  78. GRB 011211 Optical Observations: Likely Afterglow
  79. GRB011130 (=XRF011130): Further analysis of Chandra Target of
  80. GRB011211(=XRF011211): BeppoSAX refined positions
  81. BeppoSAX Alert: GRB011211(=XRF011211)
  82. GRB 011130: Optical Observations of Chandra Sources
  83. GRB 011130: Optical Observations of Chandra sources
  84. GRB011130 (XRF011130) Chandra Observations
  85. GRB011130 (=XRF011130): Scheduled Target of Opportunity
  86. GRB 011130: Magellan spectroscopy
  87. Sub-mm and Centimeter Detections of the Host Galaxy of GRB000418
  88. GRB011130, optical observations
  89. GRB 011130, K band observations
  90. GRB011130, optical observations
  91. GRB011130 (=XRF011130): Second Revised Localization by HETE
  92. GRB 011130 I-band Observation
  93. GRB011130 (XRF011130) optical observations
  94. GRB011130 (XRF011130) SDSS PT i-band observations
  95. XRF011130: Infrared Observations
  96. GRB011130, Radio Observations
  97. Detection of the X-ray afterglow of GRB011121 by BeppoSAX
  98. GRB011130 (=XRF011130), Optical Observations
  99. XRF011130: NEAT Optical Observations
  100. GRB011130 (=XRF011130): Revised Localization of an X-ray

Advanced

Download all Circulars as a .tar.gz archive:
Questions or comments?
Contact GCN directly.
Have you found a bug in GCN?
Open an issue.
Want to contribute code to GCN?
Get involved on GitHub.

gcn.nasa.gov

A service of the Astrophysics Science Division at NASA Goddard Space Flight Center

Looking for U.S. government information and services? Visit USA.gov