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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. ROTSE-IIIb Observations of GRB 040916 (HETE #3558)
  2. GRB040916 (= H3558): Improved Localization from HETE WXM
  3. GRB040916 (= H3558): A Long XRF Localized by HETE
  4. GRB040912 (= H3557): Chandra Observations Scheduled
  5. GRB 040912: Optical Observations
  6. GRB/XRF040912,optical observations
  7. GRB 040912, BVRI observations
  8. Optical observations of GRB/XRF 040912 = HETE 3557
  9. An intense burst from SGR1806-20
  10. GRB040912 : Kiso Optical follow-up observation
  11. IBAS GRB Alerts 1978-1980
  12. Optical observations of field of GRB040912
  13. HETE 3557: Optical observations
  14. GRB040912 (= H3557): A Long GRB or XRF Localized by HETE
  15. GRB 040827: XMM-Newton data
  16. GRB040903 - A XRF?
  17. GRB040827: analysis of the XMM-Newton observation
  18. GRB040903, REM near-IR observation
  19. GRB 040903 - INTEGRAL data analysis
  20. IBAS Alert 1974. Not a real GRB
  21. Very bright burst detected from SGR 1806-20
  22. ROTSE-III Rapid Response to possible GRB 040903 (INTEGRAL #1972)
  23. Possible GRB 040903 - further analysis
  24. Possible GRB 040903 detected with INTEGRAL
  25. GRB 040827 - Radio Observations
  26. XMM-Newton Images of GRB 040827
  27. GRB040825A: Optical observations
  28. GRB040825A: Optical observations
  29. GRB 040827: optical and NIR observations at the VLT
  30. GRB 040827: UKIRT - 2nd epoch K-band imaging
  31. GRB 040827: 2nd epoch of Magellan K-band imaging
  32. GRB 040827: K imaging - no evidence of variability
  33. GRB 040827: Detection of NIR afterglow
  34. GRB 040827: Possible detection of optical afterglow
  35. GRB 040827: RTT150 optical observations
  36. GRB040827 XMM-Newton observation
  37. GRB040825A: optical limit before GRB
  38. MASTER: GRB040827 possible OT
  39. GRB 040825B: Optical observations
  40. GRB040827 optical observations
  41. GRB 040827 : Planned XMM-Newton observation
  42. GRB 040827 - Refined position
  43. GRB 040827 : peak flux
  44. GRB 040827 - A long GRB detected by INTEGRAL
  45. GRB040825B, BVRcIc field photometry
  46. GRB040825A, BVRcIc field photometry
  47. GCN GRB OBSERBATION REPORT
  48. GRB 040825A,optical observations
  49. Increase of SGR 1806-20 activity
  50. GRB040825A: optical observations
  51. GRB040825B: optical observations
  52. GRB040825B (=H3510): An XRF Localized in Real Time by HETE
  53. GRB 040825A: Optical observations.
  54. MASTER: GRB040825a optical observation
  55. MASTER: GRB040825b optical observation
  56. GRB040825B: Correction to GCN 2657
  57. GRB 040825: Optical observations
  58. XRF040812: possible afterglow second Chandra observation
  59. GRB 040812: Second epoch CXO Observations
  60. GRB040823,optical observation
  61. XRF040812: GMRT observations
  62. Triangulation of GRB 040816 (Konus-Wind - Helicon-Coronas-F)
  63. XRF 040812: optical observation at VLT
  64. GRB 040812: Optical counterparts of CXO sources
  65. XRF040812: possible afterglow
  66. CXO observation of GRB 040812
  67. Bursting activity from SGR 1806-20 detected with IBAS
  68. IPN/HETE localizations of GRB040810 (=H3489)
  69. GRB 040812: Keck and LCO optical observations
  70. GRB 040812: Keck and LCO observations
  71. GRB 040812: radio observations
  72. GRB040812, optical/IR observations
  73. Konus-Wind observation of GRB040810 (=H3489)
  74. GRB 040812: a long GRB detected by INTEGRAL
  75. GRB 040810: Optical observations of a limited region
  76. XRF040701: Optical Observations at ESO
  77. IPN/HETE triangulation of GRB040802 (=H3485)
  78. GRB 040730, infrared observations
  79. GRB 040730: Optical observations
  80. GRB 040730: a long GRB detected with INTEGRAL
  81. Ongoing activity of SGR 1806-20
  82. GRB040624: optical monitoring at TNG
  83. XRF 040701 - optical observations of the decaying Chandra source
  84. XRF040701: Second-Epoch Chandra Observations
  85. Cancellation of IBAS/INTEGRAL GRB alerts
  86. XRF040701: VLA Observations
  87. XRF040701: Magellan Spectroscopy of Chandra Source #2 Associated Galaxy
  88. XRF040701: First-Epoch Chandra Observations
  89. IBAS Alert 1836: NOT a real GRB
  90. GRB040709 J,H-band observations
  91. GRB040624, optical observations
  92. GRB040706:observation at University of Miyazaki
  93. XRF 040701, optical observations
  94. XRF040701 (=U11548): a bright XRF detected by HETE
  95. GRB 040624: optical observations
  96. Optical Observations of GRB040624
  97. GRB 040624: optical observations at TNG and VLT
  98. MASTER: GRB 040624 optical observation after 0,48d
  99. GRB 040624: R-band observations
  100. GRB 040624, optical observations

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