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. Possible GRB 040903 detected with INTEGRAL
  2. GRB 040827 - Radio Observations
  3. XMM-Newton Images of GRB 040827
  4. GRB040825A: Optical observations
  5. GRB040825A: Optical observations
  6. GRB 040827: optical and NIR observations at the VLT
  7. GRB 040827: UKIRT - 2nd epoch K-band imaging
  8. GRB 040827: 2nd epoch of Magellan K-band imaging
  9. GRB 040827: K imaging - no evidence of variability
  10. GRB 040827: Detection of NIR afterglow
  11. GRB 040827: Possible detection of optical afterglow
  12. GRB 040827: RTT150 optical observations
  13. GRB040827 XMM-Newton observation
  14. GRB040825A: optical limit before GRB
  15. MASTER: GRB040827 possible OT
  16. GRB 040825B: Optical observations
  17. GRB040827 optical observations
  18. GRB 040827 : Planned XMM-Newton observation
  19. GRB 040827 - Refined position
  20. GRB 040827 : peak flux
  21. GRB 040827 - A long GRB detected by INTEGRAL
  22. GRB040825B, BVRcIc field photometry
  23. GRB040825A, BVRcIc field photometry
  24. GCN GRB OBSERBATION REPORT
  25. GRB 040825A,optical observations
  26. Increase of SGR 1806-20 activity
  27. GRB040825A: optical observations
  28. GRB040825B: optical observations
  29. GRB040825B (=H3510): An XRF Localized in Real Time by HETE
  30. GRB 040825A: Optical observations.
  31. MASTER: GRB040825a optical observation
  32. MASTER: GRB040825b optical observation
  33. GRB040825B: Correction to GCN 2657
  34. GRB 040825: Optical observations
  35. XRF040812: possible afterglow second Chandra observation
  36. GRB 040812: Second epoch CXO Observations
  37. GRB040823,optical observation
  38. XRF040812: GMRT observations
  39. Triangulation of GRB 040816 (Konus-Wind - Helicon-Coronas-F)
  40. XRF 040812: optical observation at VLT
  41. GRB 040812: Optical counterparts of CXO sources
  42. XRF040812: possible afterglow
  43. CXO observation of GRB 040812
  44. Bursting activity from SGR 1806-20 detected with IBAS
  45. IPN/HETE localizations of GRB040810 (=H3489)
  46. GRB 040812: Keck and LCO optical observations
  47. GRB 040812: Keck and LCO observations
  48. GRB 040812: radio observations
  49. GRB040812, optical/IR observations
  50. Konus-Wind observation of GRB040810 (=H3489)
  51. GRB 040812: a long GRB detected by INTEGRAL
  52. GRB 040810: Optical observations of a limited region
  53. XRF040701: Optical Observations at ESO
  54. IPN/HETE triangulation of GRB040802 (=H3485)
  55. GRB 040730, infrared observations
  56. GRB 040730: Optical observations
  57. GRB 040730: a long GRB detected with INTEGRAL
  58. Ongoing activity of SGR 1806-20
  59. GRB040624: optical monitoring at TNG
  60. XRF 040701 - optical observations of the decaying Chandra source
  61. XRF040701: Second-Epoch Chandra Observations
  62. Cancellation of IBAS/INTEGRAL GRB alerts
  63. XRF040701: VLA Observations
  64. XRF040701: Magellan Spectroscopy of Chandra Source #2 Associated Galaxy
  65. XRF040701: First-Epoch Chandra Observations
  66. IBAS Alert 1836: NOT a real GRB
  67. GRB040709 J,H-band observations
  68. GRB040624, optical observations
  69. GRB040706:observation at University of Miyazaki
  70. XRF 040701, optical observations
  71. XRF040701 (=U11548): a bright XRF detected by HETE
  72. GRB 040624: optical observations
  73. Optical Observations of GRB040624
  74. GRB 040624: optical observations at TNG and VLT
  75. MASTER: GRB 040624 optical observation after 0,48d
  76. GRB 040624: R-band observations
  77. GRB 040624, optical observations
  78. GRB 040624 - A long GRB detected with INTEGRAL
  79. GRB 030329: Rebrightening of hyperluminal ejecta.
  80. IPN Summary of SGR1806-20 Activity in 2004
  81. GRB040511: Retraction of redshift identification
  82. SGR 1806-20: no IR variability of the proposed counterparts
  83. MASTER:HETE Alert 3259 (SRG1806-20) optical observation
  84. SGR 1806-20, potential NIR counterpart
  85. GRB 040606: Optical observations
  86. MASTER: HETE Alert 3274 optical observation
  87. Activivty of SGR 1806-20
  88. IPN triangulation of an intense intermediate burst from SGR1806-20
  89. GRB 040511, very fast decay?
  90. GRB 030324: Detection and Color of Host Galaxy
  91. GRB 040511: NIR observations with REM
  92. GRB040511: Redshift identifcation
  93. GRB 040511: Optical limit
  94. GRB040511: Candidate optical/NIR afterglow
  95. IBAS GRB Alerts n.1785 to 1791
  96. GRB 040511: ROTSE-III Rapid Optical Upper Limits
  97. GRB 040511: Second Epoch Optical Observations
  98. IBAS GRB Alerts 1781-4
  99. GRB 040511: Optical observations
  100. GRB 040511: 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