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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"

28049 results found.

  1. radio observations, GRB 040924
  2. GRB040929,optical observation
  3. GRB040924,optical observation
  4. GRB040924,optical observation
  5. GRB 040924: detection of possible host galaxy by Subaru
  6. GRB040924: KAIT observations
  7. GRB040924 : Optical candidate observations at Lulin observatory
  8. GRB040924 : Optical candidate observations at Lulin observatory
  9. GRB 040924: Subaru NIR observation
  10. XRF 040912: Radio Observations
  11. XRF 040916: Radio Observations
  12. GRB040912(=H3557): Chandra Candidate X-ray Afterglow
  13. XRF040916: continuing decay of OT
  14. TAROT Observations of GRB 040916 (HETE #3558)
  15. GRB040912(=H3557): Candidate Optical Afterglow
  16. XRF040916, optical observations
  17. XRF 040912, identification of CXO sources
  18. XRF040912, BVRcIc field calibration
  19. XRF040916, BVRcIc field calibration
  20. GRB040916: Archival optical observations
  21. GRB040912(=H3557): Observations with the Chandra X-ray Observatory
  22. GRB040916: Optical observations
  23. GRB040912 (= H3557): Chandra Observations Scheduled
  24. GRB 040912: Optical Observations
  25. GRB/XRF040912,optical observations
  26. GRB 040912, BVRI observations
  27. Optical observations of field of GRB040912
  28. HETE 3557: Optical observations
  29. GRB040903 - A XRF?
  30. GRB040827: analysis of the XMM-Newton observation
  31. GRB040903, REM near-IR observation
  32. Very bright burst detected from SGR 1806-20
  33. ROTSE-III Rapid Response to possible GRB 040903 (INTEGRAL #1972)
  34. Possible GRB 040903 - further analysis
  35. GRB 040827 - Radio Observations
  36. XMM-Newton Images of GRB 040827
  37. GRB 040827: optical and NIR observations at the VLT
  38. GRB 040827: UKIRT - 2nd epoch K-band imaging
  39. GRB 040827: 2nd epoch of Magellan K-band imaging
  40. GRB 040827: K imaging - no evidence of variability
  41. GRB 040827: Detection of NIR afterglow
  42. GRB040827 XMM-Newton observation
  43. GRB040825A: optical limit before GRB
  44. GRB 040825B: Optical observations
  45. GRB 040827 : Planned XMM-Newton observation
  46. GRB040825B, BVRcIc field photometry
  47. GRB040825A, BVRcIc field photometry
  48. GCN GRB OBSERBATION REPORT
  49. GRB 040825A,optical observations
  50. GRB040825A: optical observations
  51. GRB040825B: optical observations
  52. MASTER: GRB040825b optical observation
  53. GRB 040825: Optical observations
  54. XRF040812: possible afterglow second Chandra observation
  55. GRB 040812: Second epoch CXO Observations
  56. GRB040823,optical observation
  57. XRF040812: GMRT observations
  58. XRF 040812: optical observation at VLT
  59. GRB 040812: Optical counterparts of CXO sources
  60. XRF040812: possible afterglow
  61. CXO observation of GRB 040812
  62. GRB 040812: radio observations
  63. GRB040812, optical/IR observations
  64. GRB 040812: a long GRB detected by INTEGRAL
  65. XRF040701: Optical Observations at ESO
  66. GRB 040730, infrared observations
  67. GRB 040730: a long GRB detected with INTEGRAL
  68. Ongoing activity of SGR 1806-20
  69. GRB040624: optical monitoring at TNG
  70. XRF 040701 - optical observations of the decaying Chandra source
  71. XRF040701: Second-Epoch Chandra Observations
  72. XRF040701: VLA Observations
  73. XRF040701: First-Epoch Chandra Observations
  74. GRB040624, optical observations
  75. GRB040706:observation at University of Miyazaki
  76. Optical Observations of GRB040624
  77. GRB 040624: optical observations at TNG and VLT
  78. MASTER: GRB 040624 optical observation after 0,48d
  79. GRB 040624, optical observations
  80. GRB 040624 - A long GRB detected with INTEGRAL
  81. GRB 030329: Rebrightening of hyperluminal ejecta.
  82. IPN Summary of SGR1806-20 Activity in 2004
  83. SGR 1806-20: no IR variability of the proposed counterparts
  84. MASTER:HETE Alert 3259 (SRG1806-20) optical observation
  85. SGR 1806-20, potential NIR counterpart
  86. GRB 040606: Optical observations
  87. MASTER: HETE Alert 3274 optical observation
  88. Activivty of SGR 1806-20
  89. GRB 040511, very fast decay?
  90. GRB 030324: Detection and Color of Host Galaxy
  91. GRB 040511: NIR observations with REM
  92. GRB040511: Candidate optical/NIR afterglow
  93. GRB 040511: ROTSE-III Rapid Optical Upper Limits
  94. GRB 040511: Second Epoch Optical Observations
  95. GRB 040511: Optical observations
  96. GRB 040511: Optical Observations
  97. GRB040511: Optical Observations
  98. GRB040511: Optical Observations
  99. Type Ic SN2001em (off-axis GRB jet?), optical spectrum
  100. GRB 040423 (=H3175): A Long GRB Localized by HETE

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