Skip to main content
Due to the lapse in federal government funding, NASA is not updating this website. See the Operations FAQ for GCN impacts.
New! Super-Kamiokande JSON Notices and Schema v4.5.0. 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"

25820 results found.

  1. GRB020405 field photometry at ESO
  2. XRF020427: Chandra Observations and Candidate X-ray Counterparts
  3. GRB(XRF) 020427: X-ray afterglow with BeppoSAX
  4. GRB020321 : Optical observations.
  5. XRF 020427
  6. GRB 020124: Optical observations
  7. IPN triangulation of GRB020418
  8. GRB020405: VLT observations of the OT environment
  9. IPN triangulation of GRB020413
  10. GRB020405: predicted break
  11. GRB 020409: No Evidence for an Optical Afterglow
  12. GRB 020331 Kyoto observation on March 31
  13. GRB020410: BeppoSAX NFI observation
  14. X-ray afterglow of GRB020321
  15. GRB020331 optical observations with RIMOTS
  16. GRB020124 optical observations with RIBOTS/RIMOTS
  17. GRB 020321: Candidate X-ray Counterparts
  18. GRB020406(?), optical observations
  19. GRB 020405: Decay index
  20. Short RXTE/ASM transient 020406; may be a GRB
  21. GRB020405, Radio Observations
  22. GRB 020405, U-band observations
  23. GRB011212: Optical Observations
  24. GRB 020331: NIR Observations
  25. GRB020331 NIR observation at KPNO (re-submission)
  26. GRB02033 NIR observation at KPNO
  27. GRB020331 field photometry
  28. GRB 020331, NIR observations
  29. GRB020331(=H1963): The "Easter" Burst Detected by HETE
  30. GRB 020322: BeppoSAX observations of the X-ray afterglow
  31. GRB011211: HST Observations of Optical Afterglow and Host Galaxy
  32. Near-Infrared Observations of GRB020322 at TIRGO
  33. GRB 020321, Radio Observations
  34. GRB 020322: Optical Observations
  35. GRB020127: Proposed Host Galaxy Detection and Identification of Afterglow
  36. GRB 020321: Optical observations
  37. GRB020317 BVRI field photometry
  38. GRB011211 revised BVRI field photometry
  39. GRB020305 BVRI field photometry
  40. GRB020322 BVRI field photometry
  41. GRB 020322: Optical Sources and Improved Astrometry
  42. GRB020317: optical observations
  43. GRB020321 optical observations
  44. GRB020321: a faint BeppoSAX detection
  45. GRB 020317 : KISO Optical Observations
  46. GRB020317 (=H1959): Localization by HETE of a Low Fluence GRB
  47. GRB 020305: Optical Observations
  48. GRB020317, optical observations
  49. GRB 020317: Optical observations
  50. GRB 011121: Third HST Epoch
  51. GRB020305: Properties of the Candidate Optical Afterglow
  52. GRB 011121: HST Observations reveal an intermediate-time multicolor
  53. GRB011130 (XRF011130) Second Epoch Chandra Observations
  54. GRB020305: Subaru Optical Observations
  55. XRF/GRB 011030: Detection of the Probable Host Galaxy
  56. GRB 020305: Candidate optical afterglow
  57. GRB020305, optical observations
  58. IPN triangulation of GRB020305 (HETE 1939)
  59. GRB020305 (=H1939): Localization of a GRB by HETE
  60. HST Imaging of the afterglow and host of GRB 011121
  61. IPN detection and localization of Cygnus X-1 flares
  62. SGR1900+14 activity
  63. IPN Upper Limits to a GRB Associated With SN2002ap
  64. GRB020124 BVRI field photometry
  65. GRB020127: Comparison of Chandra Epochs and Identification of Possible Counterparts
  66. SN2002ap (SN/GRB?) Echelle spectra
  67. GRB020127 Optical Observations
  68. SN 2002ap in M74
  69. SN2002ap (SN/GRB?) UBVRI Field Photometry
  70. GRB020127: Chandra Observations and Prospective Counterparts
  71. pre-SN2002ap (SN/GRB?) imaging of M74
  72. Type Ib/c SN2002ap (SN/GRB?) Radio Observations
  73. GRB020124, optical observations
  74. GRB 020127, I-band observations starting 3.14-hr after the event
  75. GRB010921 Optical Observations
  76. GRB020127(=H1902): Localization of a Double-Peaked GRB by HETE
  77. GRB020124: Optical observations
  78. GRB 020124: Optical observations
  79. GRB 020124: Optical afterglow
  80. GRB020124(=H1896): Localization of a Long GRB by HETE
  81. Possible optical counterpart to a GRB
  82. GRB011212, Optical Observations
  83. Optical polarization observations for GRB011211
  84. GRB 011211: Detection of the Probable Host Galaxy
  85. GRB 011130 and GRB 011212 - Milagro GeV/TeV Observations
  86. GRB 011130: Optical Observations of X-ray and Radio Sources
  87. GRB 011212: optical observation at Asiago
  88. GRB 011211: Evidence for an Optical Break
  89. GRB 011211: TNG Spectroscopic Observations
  90. optical follow-up of GRB(XRF) 011211
  91. GRB 011212: optical observation at Oslo (relayed)
  92. GRB 011211, Optical Observations
  93. GRB011212, BVRI field photometry
  94. GRB011211, BVRI field photometry
  95. GRB011212 (=H10001): An X-Ray Rich GRB Detected by HETE
  96. Fading of the optical source associated of XRF 011211
  97. GRB 011211 Optical Observations: Likely Afterglow
  98. GRB011130 (=XRF011130): Further analysis of Chandra Target of
  99. GRB011130 (XRF011130) Chandra Observations
  100. GRB011130 (=XRF011130): Scheduled Target of Opportunity

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