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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. IBAS Alert 1974. Not a real GRB
  2. Very bright burst detected from SGR 1806-20
  3. ROTSE-III Rapid Response to possible GRB 040903 (INTEGRAL #1972)
  4. Possible GRB 040903 - further analysis
  5. Possible GRB 040903 detected with INTEGRAL
  6. GRB 040827 - Radio Observations
  7. XMM-Newton Images of GRB 040827
  8. GRB040825A: Optical observations
  9. GRB040825A: Optical observations
  10. GRB 040827: optical and NIR observations at the VLT
  11. GRB 040827: UKIRT - 2nd epoch K-band imaging
  12. GRB 040827: 2nd epoch of Magellan K-band imaging
  13. GRB 040827: K imaging - no evidence of variability
  14. GRB 040827: Detection of NIR afterglow
  15. GRB 040827: Possible detection of optical afterglow
  16. GRB 040827: RTT150 optical observations
  17. GRB040827 XMM-Newton observation
  18. GRB040825A: optical limit before GRB
  19. MASTER: GRB040827 possible OT
  20. GRB 040825B: Optical observations
  21. GRB040827 optical observations
  22. GRB 040827 : Planned XMM-Newton observation
  23. GRB 040827 - Refined position
  24. GRB 040827 : peak flux
  25. GRB 040827 - A long GRB detected by INTEGRAL
  26. GRB040825B, BVRcIc field photometry
  27. GRB040825A, BVRcIc field photometry
  28. GCN GRB OBSERBATION REPORT
  29. GRB 040825A,optical observations
  30. Increase of SGR 1806-20 activity
  31. GRB040825A: optical observations
  32. GRB040825B: optical observations
  33. GRB040825B (=H3510): An XRF Localized in Real Time by HETE
  34. GRB 040825A: Optical observations.
  35. MASTER: GRB040825a optical observation
  36. MASTER: GRB040825b optical observation
  37. GRB040825B: Correction to GCN 2657
  38. GRB 040825: Optical observations
  39. XRF040812: possible afterglow second Chandra observation
  40. GRB 040812: Second epoch CXO Observations
  41. GRB040823,optical observation
  42. XRF040812: GMRT observations
  43. Triangulation of GRB 040816 (Konus-Wind - Helicon-Coronas-F)
  44. XRF 040812: optical observation at VLT
  45. GRB 040812: Optical counterparts of CXO sources
  46. XRF040812: possible afterglow
  47. CXO observation of GRB 040812
  48. Bursting activity from SGR 1806-20 detected with IBAS
  49. IPN/HETE localizations of GRB040810 (=H3489)
  50. GRB 040812: Keck and LCO optical observations
  51. GRB 040812: Keck and LCO observations
  52. GRB 040812: radio observations
  53. GRB040812, optical/IR observations
  54. Konus-Wind observation of GRB040810 (=H3489)
  55. GRB 040812: a long GRB detected by INTEGRAL
  56. GRB 040810: Optical observations of a limited region
  57. XRF040701: Optical Observations at ESO
  58. IPN/HETE triangulation of GRB040802 (=H3485)
  59. GRB 040730, infrared observations
  60. GRB 040730: Optical 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. Cancellation of IBAS/INTEGRAL GRB alerts
  67. XRF040701: VLA Observations
  68. XRF040701: Magellan Spectroscopy of Chandra Source #2 Associated Galaxy
  69. XRF040701: First-Epoch Chandra Observations
  70. IBAS Alert 1836: NOT a real GRB
  71. GRB040709 J,H-band observations
  72. GRB040624, optical observations
  73. GRB040706:observation at University of Miyazaki
  74. XRF 040701, optical observations
  75. XRF040701 (=U11548): a bright XRF detected by HETE
  76. GRB 040624: optical observations
  77. Optical Observations of GRB040624
  78. GRB 040624: optical observations at TNG and VLT
  79. MASTER: GRB 040624 optical observation after 0,48d
  80. GRB 040624: R-band observations
  81. GRB 040624, optical observations
  82. GRB 040624 - A long GRB detected with INTEGRAL
  83. GRB 030329: Rebrightening of hyperluminal ejecta.
  84. IPN Summary of SGR1806-20 Activity in 2004
  85. GRB040511: Retraction of redshift identification
  86. SGR 1806-20: no IR variability of the proposed counterparts
  87. MASTER:HETE Alert 3259 (SRG1806-20) optical observation
  88. SGR 1806-20, potential NIR counterpart
  89. GRB 040606: Optical observations
  90. MASTER: HETE Alert 3274 optical observation
  91. Activivty of SGR 1806-20
  92. IPN triangulation of an intense intermediate burst from SGR1806-20
  93. GRB 040511, very fast decay?
  94. GRB 030324: Detection and Color of Host Galaxy
  95. GRB 040511: NIR observations with REM
  96. GRB040511: Redshift identifcation
  97. GRB 040511: Optical limit
  98. GRB040511: Candidate optical/NIR afterglow
  99. IBAS GRB Alerts n.1785 to 1791
  100. GRB 040511: ROTSE-III Rapid Optical Upper Limits

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