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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. GRB040903, REM near-IR observation
  2. GRB 040903 - INTEGRAL data analysis
  3. IBAS Alert 1974. Not a real GRB
  4. Very bright burst detected from SGR 1806-20
  5. ROTSE-III Rapid Response to possible GRB 040903 (INTEGRAL #1972)
  6. Possible GRB 040903 - further analysis
  7. Possible GRB 040903 detected with INTEGRAL
  8. GRB 040827 - Radio Observations
  9. XMM-Newton Images of GRB 040827
  10. GRB040825A: Optical observations
  11. GRB040825A: Optical observations
  12. GRB 040827: optical and NIR observations at the VLT
  13. GRB 040827: UKIRT - 2nd epoch K-band imaging
  14. GRB 040827: 2nd epoch of Magellan K-band imaging
  15. GRB 040827: K imaging - no evidence of variability
  16. GRB 040827: Detection of NIR afterglow
  17. GRB 040827: Possible detection of optical afterglow
  18. GRB 040827: RTT150 optical observations
  19. GRB040827 XMM-Newton observation
  20. GRB040825A: optical limit before GRB
  21. MASTER: GRB040827 possible OT
  22. GRB 040825B: Optical observations
  23. GRB040827 optical observations
  24. GRB 040827 : Planned XMM-Newton observation
  25. GRB 040827 - Refined position
  26. GRB 040827 : peak flux
  27. GRB 040827 - A long GRB detected by INTEGRAL
  28. GRB040825B, BVRcIc field photometry
  29. GRB040825A, BVRcIc field photometry
  30. GCN GRB OBSERBATION REPORT
  31. GRB 040825A,optical observations
  32. Increase of SGR 1806-20 activity
  33. GRB040825A: optical observations
  34. GRB040825B: optical observations
  35. GRB040825B (=H3510): An XRF Localized in Real Time by HETE
  36. GRB 040825A: Optical observations.
  37. MASTER: GRB040825a optical observation
  38. MASTER: GRB040825b optical observation
  39. GRB040825B: Correction to GCN 2657
  40. GRB 040825: Optical observations
  41. XRF040812: possible afterglow second Chandra observation
  42. GRB 040812: Second epoch CXO Observations
  43. GRB040823,optical observation
  44. XRF040812: GMRT observations
  45. Triangulation of GRB 040816 (Konus-Wind - Helicon-Coronas-F)
  46. XRF 040812: optical observation at VLT
  47. GRB 040812: Optical counterparts of CXO sources
  48. XRF040812: possible afterglow
  49. CXO observation of GRB 040812
  50. Bursting activity from SGR 1806-20 detected with IBAS
  51. IPN/HETE localizations of GRB040810 (=H3489)
  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. Konus-Wind observation of GRB040810 (=H3489)
  57. GRB 040812: a long GRB detected by INTEGRAL
  58. GRB 040810: Optical observations of a limited region
  59. XRF040701: Optical Observations at ESO
  60. IPN/HETE triangulation of GRB040802 (=H3485)
  61. GRB 040730, infrared observations
  62. GRB 040730: Optical observations
  63. GRB 040730: a long GRB detected with INTEGRAL
  64. Ongoing activity of SGR 1806-20
  65. GRB040624: optical monitoring at TNG
  66. XRF 040701 - optical observations of the decaying Chandra source
  67. XRF040701: Second-Epoch Chandra Observations
  68. Cancellation of IBAS/INTEGRAL GRB alerts
  69. XRF040701: VLA Observations
  70. XRF040701: Magellan Spectroscopy of Chandra Source #2 Associated Galaxy
  71. XRF040701: First-Epoch Chandra Observations
  72. IBAS Alert 1836: NOT a real GRB
  73. GRB040709 J,H-band observations
  74. Subject: GRB040624, optical observations
  75. GRB040706:observation at University of Miyazaki
  76. XRF 040701, optical observations
  77. XRF040701 (=U11548): a bright XRF detected by HETE
  78. GRB 040624: optical observations
  79. Optical Observations of GRB040624
  80. GRB 040624: optical observations at TNG and VLT
  81. MASTER: GRB 040624 optical observation after 0,48d
  82. GRB 040624: R-band observations
  83. GRB 040624, optical observations
  84. GRB 040624 - A long GRB detected with INTEGRAL
  85. GRB 030329: Rebrightening of hyperluminal ejecta.
  86. IPN Summary of SGR1806-20 Activity in 2004
  87. GRB040511: Retraction of redshift identification
  88. SGR 1806-20: no IR variability of the proposed counterparts
  89. MASTER:HETE Alert 3259 (SRG1806-20) optical observation
  90. SGR 1806-20, potential NIR counterpart
  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. GRB040511: Candidate optical/NIR afterglow

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