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"

32796 results found.

  1. GRB040912(=H3557): Chandra Candidate X-ray Afterglow
  2. XRF040916: continuing decay of OT
  3. TAROT Observations of GRB 040916 (HETE #3558)
  4. XRF040916, optical observations
  5. XRF040916: Optical Transient Candidate by Subaru
  6. GRB040916 optical limits 17 min after GRB
  7. XRF 040912 (=H3557): Spectral and Temporal Properties
  8. XRF040916, Ic observations
  9. XRF040912, BVRcIc field calibration
  10. XRF040916, BVRcIc field calibration
  11. GRB040916: Archival optical observations
  12. GRB040912(=H3557): Observations with the Chandra X-ray Observatory
  13. GRB040916: Optical observations
  14. ROTSE-IIIb Observations of GRB 040916 (HETE #3558)
  15. GRB040912 (= H3557): Chandra Observations Scheduled
  16. GRB 040912: Optical Observations
  17. GRB/XRF040912,optical observations
  18. GRB 040912, BVRI observations
  19. Optical observations of GRB/XRF 040912 = HETE 3557
  20. An intense burst from SGR1806-20
  21. IBAS GRB Alerts 1978-1980
  22. Optical observations of field of GRB040912
  23. GRB040912 (= H3557): A Long GRB or XRF Localized by HETE
  24. GRB 040827: XMM-Newton data
  25. GRB040903 - A XRF?
  26. GRB040827: analysis of the XMM-Newton observation
  27. GRB 040903 - INTEGRAL data analysis
  28. IBAS Alert 1974. Not a real GRB
  29. Very bright burst detected from SGR 1806-20
  30. ROTSE-III Rapid Response to possible GRB 040903 (INTEGRAL #1972)
  31. Possible GRB 040903 - further analysis
  32. Possible GRB 040903 detected with INTEGRAL
  33. GRB 040827 - Radio Observations
  34. XMM-Newton Images of GRB 040827
  35. GRB 040827: optical and NIR observations at the VLT
  36. GRB 040827: UKIRT - 2nd epoch K-band imaging
  37. GRB 040827: 2nd epoch of Magellan K-band imaging
  38. GRB 040827: K imaging - no evidence of variability
  39. GRB 040827: Detection of NIR afterglow
  40. GRB 040827: Possible detection of optical afterglow
  41. GRB 040827: RTT150 optical observations
  42. GRB040825A: optical limit before GRB
  43. GRB 040825B: Optical observations
  44. GRB040827 optical observations
  45. GRB 040827 : Planned XMM-Newton observation
  46. GRB 040827 - Refined position
  47. GRB 040827 : peak flux
  48. GRB 040827 - A long GRB detected by INTEGRAL
  49. GRB040825B, BVRcIc field photometry
  50. GRB040825A, BVRcIc field photometry
  51. GCN GRB OBSERBATION REPORT
  52. GRB 040825A,optical observations
  53. Increase of SGR 1806-20 activity
  54. GRB 040825A: Optical observations.
  55. GRB040825B: Correction to GCN 2657
  56. GRB 040825: Optical observations
  57. GRB 040812: Second epoch CXO Observations
  58. GRB040823,optical observation
  59. Triangulation of GRB 040816 (Konus-Wind - Helicon-Coronas-F)
  60. XRF 040812: optical observation at VLT
  61. GRB 040812: Optical counterparts of CXO sources
  62. XRF040812: possible afterglow
  63. CXO observation of GRB 040812
  64. IPN/HETE localizations of GRB040810 (=H3489)
  65. GRB 040812: Keck and LCO optical observations
  66. GRB 040812: Keck and LCO observations
  67. GRB 040812: radio observations
  68. GRB040812, optical/IR observations
  69. Konus-Wind observation of GRB040810 (=H3489)
  70. GRB 040812: a long GRB detected by INTEGRAL
  71. GRB 040810: Optical observations of a limited region
  72. IPN/HETE triangulation of GRB040802 (=H3485)
  73. GRB 040730, infrared observations
  74. GRB 040730: Optical observations
  75. GRB 040730: a long GRB detected with INTEGRAL
  76. Ongoing activity of SGR 1806-20
  77. GRB040624: optical monitoring at TNG
  78. Cancellation of IBAS/INTEGRAL GRB alerts
  79. IBAS Alert 1836: NOT a real GRB
  80. GRB040709 J,H-band observations
  81. GRB 040624: optical observations
  82. GRB 040624: optical observations at TNG and VLT
  83. MASTER: GRB 040624 optical observation after 0,48d
  84. GRB 040624: R-band observations
  85. GRB 040624, optical observations
  86. GRB 040624 - A long GRB detected with INTEGRAL
  87. GRB 030329: Rebrightening of hyperluminal ejecta.
  88. IPN Summary of SGR1806-20 Activity in 2004
  89. GRB040511: Retraction of redshift identification
  90. MASTER:HETE Alert 3259 (SRG1806-20) optical observation
  91. GRB 040606: Optical observations
  92. MASTER: HETE Alert 3274 optical observation
  93. Activivty of SGR 1806-20
  94. IPN triangulation of an intense intermediate burst from SGR1806-20
  95. GRB 040511, very fast decay?
  96. GRB 030324: Detection and Color of Host Galaxy
  97. GRB 040511: NIR observations with REM
  98. GRB040511: Redshift identifcation
  99. GRB 040511: Optical limit
  100. IBAS GRB Alerts n.1785 to 1791

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