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"

25718 results found.

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

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