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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"

28048 results found.

  1. GRB040929,optical observation
  2. GRB040924,optical observation
  3. GRB040924,optical observation
  4. GRB 040924: detection of possible host galaxy by Subaru
  5. GRB040924: KAIT observations
  6. GRB040924 : Optical candidate observations at Lulin observatory
  7. GRB040924 : Optical candidate observations at Lulin observatory
  8. GRB 040924: Subaru NIR observation
  9. XRF 040912: Radio Observations
  10. XRF 040916: Radio Observations
  11. GRB040912(=H3557): Chandra Candidate X-ray Afterglow
  12. XRF040916: continuing decay of OT
  13. TAROT Observations of GRB 040916 (HETE #3558)
  14. GRB040912(=H3557): Candidate Optical Afterglow
  15. XRF040916, optical observations
  16. XRF 040912, identification of CXO sources
  17. XRF040912, BVRcIc field calibration
  18. XRF040916, BVRcIc field calibration
  19. GRB040916: Archival optical observations
  20. GRB040912(=H3557): Observations with the Chandra X-ray Observatory
  21. GRB040916: Optical observations
  22. GRB040912 (= H3557): Chandra Observations Scheduled
  23. GRB 040912: Optical Observations
  24. GRB/XRF040912,optical observations
  25. GRB 040912, BVRI observations
  26. Optical observations of field of GRB040912
  27. HETE 3557: Optical observations
  28. GRB040903 - A XRF?
  29. GRB040827: analysis of the XMM-Newton observation
  30. GRB040903, REM near-IR observation
  31. Very bright burst detected from SGR 1806-20
  32. ROTSE-III Rapid Response to possible GRB 040903 (INTEGRAL #1972)
  33. Possible GRB 040903 - further analysis
  34. GRB 040827 - Radio Observations
  35. XMM-Newton Images of GRB 040827
  36. GRB 040827: optical and NIR observations at the VLT
  37. GRB 040827: UKIRT - 2nd epoch K-band imaging
  38. GRB 040827: 2nd epoch of Magellan K-band imaging
  39. GRB 040827: K imaging - no evidence of variability
  40. GRB 040827: Detection of NIR afterglow
  41. GRB040827 XMM-Newton observation
  42. GRB040825A: optical limit before GRB
  43. GRB 040825B: Optical observations
  44. GRB 040827 : Planned XMM-Newton observation
  45. GRB040825B, BVRcIc field photometry
  46. GRB040825A, BVRcIc field photometry
  47. GCN GRB OBSERBATION REPORT
  48. GRB 040825A,optical observations
  49. GRB040825A: optical observations
  50. GRB040825B: optical observations
  51. MASTER: GRB040825b optical observation
  52. GRB 040825: Optical observations
  53. XRF040812: possible afterglow second Chandra observation
  54. GRB 040812: Second epoch CXO Observations
  55. GRB040823,optical observation
  56. XRF040812: GMRT observations
  57. XRF 040812: optical observation at VLT
  58. GRB 040812: Optical counterparts of CXO sources
  59. XRF040812: possible afterglow
  60. CXO observation of GRB 040812
  61. GRB 040812: radio observations
  62. GRB040812, optical/IR observations
  63. GRB 040812: a long GRB detected by INTEGRAL
  64. XRF040701: Optical Observations at ESO
  65. GRB 040730, infrared observations
  66. GRB 040730: a long GRB detected with INTEGRAL
  67. Ongoing activity of SGR 1806-20
  68. GRB040624: optical monitoring at TNG
  69. XRF 040701 - optical observations of the decaying Chandra source
  70. XRF040701: Second-Epoch Chandra Observations
  71. XRF040701: VLA Observations
  72. XRF040701: First-Epoch Chandra Observations
  73. GRB040624, optical observations
  74. GRB040706:observation at University of Miyazaki
  75. Optical Observations of GRB040624
  76. GRB 040624: optical observations at TNG and VLT
  77. MASTER: GRB 040624 optical observation after 0,48d
  78. GRB 040624, optical observations
  79. GRB 040624 - A long GRB detected with INTEGRAL
  80. GRB 030329: Rebrightening of hyperluminal ejecta.
  81. IPN Summary of SGR1806-20 Activity in 2004
  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. GRB 040511, very fast decay?
  89. GRB 030324: Detection and Color of Host Galaxy
  90. GRB 040511: NIR observations with REM
  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 : I-band follow-up observation at Lulin Observatory

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