Skip to main content
Updates to LVK & CHIME Notices, Schema v7.2.3! 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"

26500 results found.

  1. XRF040916, BVRcIc field calibration
  2. XRF 040916, optical follow-up
  3. GRB040912(=H3557): Observations with the Chandra X-ray Observatory
  4. GRB040916: Optical observations
  5. ROTSE-IIIb Observations of GRB 040916 (HETE #3558)
  6. GRB 040912: Optical Observations
  7. GRB/XRF040912,optical observations
  8. GRB 040912, BVRI observations
  9. Optical observations of GRB/XRF 040912 = HETE 3557
  10. GRB040912 : Kiso Optical follow-up observation
  11. Optical observations of field of GRB040912
  12. HETE 3557: Optical observations
  13. GRB040912 (= H3557): A Long GRB or XRF Localized by HETE
  14. GRB040903 - A XRF?
  15. GRB040827: analysis of the XMM-Newton observation
  16. GRB040903, REM near-IR observation
  17. Very bright burst detected from SGR 1806-20
  18. ROTSE-III Rapid Response to possible GRB 040903 (INTEGRAL #1972)
  19. GRB 040827 - Radio Observations
  20. XMM-Newton Images of GRB 040827
  21. GRB040825A: Optical observations
  22. GRB040825A: Optical observations
  23. GRB 040827: optical and NIR observations at the VLT
  24. GRB 040827: UKIRT - 2nd epoch K-band imaging
  25. GRB 040827: 2nd epoch of Magellan K-band imaging
  26. GRB 040827: K imaging - no evidence of variability
  27. GRB 040827: Detection of NIR afterglow
  28. GRB 040827: RTT150 optical observations
  29. GRB040827 XMM-Newton observation
  30. GRB040825A: optical limit before GRB
  31. GRB 040825B: Optical observations
  32. GRB 040827 : Planned XMM-Newton observation
  33. GRB040825B, BVRcIc field photometry
  34. GRB040825A, BVRcIc field photometry
  35. GCN GRB OBSERBATION REPORT
  36. GRB 040825A,optical observations
  37. Increase of SGR 1806-20 activity
  38. GRB040825A: optical observations
  39. GRB040825B: optical observations
  40. GRB040825B (=H3510): An XRF Localized in Real Time by HETE
  41. GRB 040825A: Optical observations.
  42. GRB040825B: Correction to GCN 2657
  43. XRF040812: possible afterglow second Chandra observation
  44. GRB 040812: Second epoch CXO Observations
  45. GRB040823,optical observation
  46. XRF040812: GMRT observations
  47. XRF 040812: optical observation at VLT
  48. GRB 040812: Optical counterparts of CXO sources
  49. XRF040812: possible afterglow
  50. CXO observation of GRB 040812
  51. Bursting activity from SGR 1806-20 detected with IBAS
  52. GRB 040812: Keck and LCO optical observations
  53. GRB 040812: Keck and LCO observations
  54. GRB 040812: radio observations
  55. GRB040812, optical/IR observations
  56. GRB 040812: a long GRB detected by INTEGRAL
  57. GRB 040810: Optical observations of a limited region
  58. XRF040701: Optical Observations at ESO
  59. IPN/HETE triangulation of GRB040802 (=H3485)
  60. GRB 040730, infrared observations
  61. GRB 040730: a long GRB detected with INTEGRAL
  62. Ongoing activity of SGR 1806-20
  63. GRB040624: optical monitoring at TNG
  64. XRF 040701 - optical observations of the decaying Chandra source
  65. XRF040701: Second-Epoch Chandra Observations
  66. XRF040701: VLA Observations
  67. XRF040701: Magellan Spectroscopy of Chandra Source #2 Associated Galaxy
  68. XRF040701: First-Epoch Chandra Observations
  69. GRB040709 J,H-band observations
  70. GRB040624, optical observations
  71. GRB040706:observation at University of Miyazaki
  72. XRF 040701, optical observations
  73. XRF040701 (=U11548): a bright XRF detected by HETE
  74. Optical Observations of GRB040624
  75. GRB 040624: optical observations at TNG and VLT
  76. MASTER: GRB 040624 optical observation after 0,48d
  77. GRB 040624: R-band observations
  78. GRB 040624, optical observations
  79. GRB 030329: Rebrightening of hyperluminal ejecta.
  80. IPN Summary of SGR1806-20 Activity in 2004
  81. SGR 1806-20: no IR variability of the proposed counterparts
  82. MASTER:HETE Alert 3259 (SRG1806-20) optical observation
  83. GRB 040606: Optical observations
  84. MASTER: HETE Alert 3274 optical observation
  85. Activivty of SGR 1806-20
  86. IPN triangulation of an intense intermediate burst from SGR1806-20
  87. GRB 040511, very fast decay?
  88. GRB 030324: Detection and Color of Host Galaxy
  89. GRB 040511: NIR observations with REM
  90. GRB040511: Redshift identifcation
  91. GRB040511: Candidate optical/NIR afterglow
  92. GRB 040511: ROTSE-III Rapid Optical Upper Limits
  93. GRB 040511: Second Epoch Optical Observations
  94. GRB 040511: Optical observations
  95. GRB 040511: Optical Observations
  96. GRB040511: Optical Observations
  97. GRB040511: Optical Observations
  98. Type Ic SN2001em (off-axis GRB jet?), optical spectrum
  99. GRB 040423 (=H3175): A Long GRB Localized by HETE
  100. GRB040422, optical observations at Loiano

Advanced

Download all Circulars as a .tar.gz archive (updated once a day):
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