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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"

28045 results found.

  1. GRB 040924: detection of possible host galaxy by Subaru
  2. GRB040924: KAIT observations
  3. GRB040924 : Optical candidate observations at Lulin observatory
  4. GRB040924 : Optical candidate observations at Lulin observatory
  5. GRB 040924: Subaru NIR observation
  6. XRF 040912: Radio Observations
  7. XRF 040916: Radio Observations
  8. GRB040912(=H3557): Chandra Candidate X-ray Afterglow
  9. XRF040916: continuing decay of OT
  10. TAROT Observations of GRB 040916 (HETE #3558)
  11. GRB040912(=H3557): Candidate Optical Afterglow
  12. XRF040916, optical observations
  13. XRF 040912, identification of CXO sources
  14. XRF040912, BVRcIc field calibration
  15. XRF040916, BVRcIc field calibration
  16. GRB040916: Archival optical observations
  17. GRB040912(=H3557): Observations with the Chandra X-ray Observatory
  18. GRB040916: Optical observations
  19. GRB040912 (= H3557): Chandra Observations Scheduled
  20. GRB 040912: Optical Observations
  21. GRB/XRF040912,optical observations
  22. GRB 040912, BVRI observations
  23. Optical observations of field of GRB040912
  24. HETE 3557: Optical observations
  25. GRB040903 - A XRF?
  26. GRB040827: analysis of the XMM-Newton observation
  27. GRB040903, REM near-IR observation
  28. Very bright burst detected from SGR 1806-20
  29. ROTSE-III Rapid Response to possible GRB 040903 (INTEGRAL #1972)
  30. Possible GRB 040903 - further analysis
  31. GRB 040827 - Radio Observations
  32. XMM-Newton Images of GRB 040827
  33. GRB 040827: optical and NIR observations at the VLT
  34. GRB 040827: UKIRT - 2nd epoch K-band imaging
  35. GRB 040827: 2nd epoch of Magellan K-band imaging
  36. GRB 040827: K imaging - no evidence of variability
  37. GRB 040827: Detection of NIR afterglow
  38. GRB040827 XMM-Newton observation
  39. GRB040825A: optical limit before GRB
  40. GRB 040825B: Optical observations
  41. GRB 040827 : Planned XMM-Newton observation
  42. GRB040825B, BVRcIc field photometry
  43. GRB040825A, BVRcIc field photometry
  44. GCN GRB OBSERBATION REPORT
  45. GRB 040825A,optical observations
  46. GRB040825A: optical observations
  47. GRB040825B: optical observations
  48. MASTER: GRB040825b optical observation
  49. GRB 040825: Optical observations
  50. XRF040812: possible afterglow second Chandra observation
  51. GRB 040812: Second epoch CXO Observations
  52. GRB040823,optical observation
  53. XRF040812: GMRT observations
  54. XRF 040812: optical observation at VLT
  55. GRB 040812: Optical counterparts of CXO sources
  56. XRF040812: possible afterglow
  57. CXO observation of GRB 040812
  58. GRB 040812: radio observations
  59. GRB040812, optical/IR observations
  60. GRB 040812: a long GRB detected by INTEGRAL
  61. XRF040701: Optical Observations at ESO
  62. GRB 040730, infrared 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. XRF040701: VLA Observations
  69. XRF040701: First-Epoch Chandra Observations
  70. GRB040624, optical observations
  71. GRB040706:observation at University of Miyazaki
  72. Optical Observations of GRB040624
  73. GRB 040624: optical observations at TNG and VLT
  74. MASTER: GRB 040624 optical observation after 0,48d
  75. GRB 040624, optical observations
  76. GRB 040624 - A long GRB detected with INTEGRAL
  77. GRB 030329: Rebrightening of hyperluminal ejecta.
  78. IPN Summary of SGR1806-20 Activity in 2004
  79. SGR 1806-20: no IR variability of the proposed counterparts
  80. MASTER:HETE Alert 3259 (SRG1806-20) optical observation
  81. SGR 1806-20, potential NIR counterpart
  82. GRB 040606: Optical observations
  83. MASTER: HETE Alert 3274 optical observation
  84. Activivty of SGR 1806-20
  85. GRB 040511, very fast decay?
  86. GRB 030324: Detection and Color of Host Galaxy
  87. GRB 040511: NIR observations with REM
  88. GRB040511: Candidate optical/NIR afterglow
  89. GRB 040511: ROTSE-III Rapid Optical Upper Limits
  90. GRB 040511: Second Epoch Optical Observations
  91. GRB 040511: Optical observations
  92. GRB 040511: Optical Observations
  93. GRB040511: Optical Observations
  94. GRB040511: Optical Observations
  95. Type Ic SN2001em (off-axis GRB jet?), optical spectrum
  96. GRB 040423 (=H3175): A Long GRB Localized by HETE
  97. GRB040422 : I-band follow-up observation at Lulin Observatory
  98. GRB 040422: ROTSE-IIIb Prompt Optical Limits
  99. GRB040422, BVRcIc field calibration
  100. GRB 040422,optical observation

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