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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"

28042 results found.

  1. GRB040924 : Optical candidate observations at Lulin observatory
  2. GRB 040924: Subaru NIR observation
  3. XRF 040912: Radio Observations
  4. XRF 040916: Radio Observations
  5. GRB040912(=H3557): Chandra Candidate X-ray Afterglow
  6. XRF040916: continuing decay of OT
  7. TAROT Observations of GRB 040916 (HETE #3558)
  8. GRB040912(=H3557): Candidate Optical Afterglow
  9. XRF040916, optical observations
  10. XRF 040912, identification of CXO sources
  11. XRF040912, BVRcIc field calibration
  12. XRF040916, BVRcIc field calibration
  13. GRB040916: Archival optical observations
  14. GRB040912(=H3557): Observations with the Chandra X-ray Observatory
  15. GRB040916: Optical observations
  16. GRB040912 (= H3557): Chandra Observations Scheduled
  17. GRB 040912: Optical Observations
  18. GRB/XRF040912,optical observations
  19. GRB 040912, BVRI observations
  20. Optical observations of field of GRB040912
  21. HETE 3557: Optical observations
  22. GRB040903 - A XRF?
  23. GRB040827: analysis of the XMM-Newton observation
  24. GRB040903, REM near-IR observation
  25. Very bright burst detected from SGR 1806-20
  26. ROTSE-III Rapid Response to possible GRB 040903 (INTEGRAL #1972)
  27. Possible GRB 040903 - further analysis
  28. GRB 040827 - Radio Observations
  29. XMM-Newton Images of GRB 040827
  30. GRB 040827: optical and NIR observations at the VLT
  31. GRB 040827: UKIRT - 2nd epoch K-band imaging
  32. GRB 040827: 2nd epoch of Magellan K-band imaging
  33. GRB 040827: K imaging - no evidence of variability
  34. GRB 040827: Detection of NIR afterglow
  35. GRB040827 XMM-Newton observation
  36. GRB040825A: optical limit before GRB
  37. GRB 040825B: Optical observations
  38. GRB 040827 : Planned XMM-Newton observation
  39. GRB040825B, BVRcIc field photometry
  40. GRB040825A, BVRcIc field photometry
  41. GCN GRB OBSERBATION REPORT
  42. GRB 040825A,optical observations
  43. GRB040825A: optical observations
  44. GRB040825B: optical observations
  45. MASTER: GRB040825b optical observation
  46. GRB 040825: Optical observations
  47. XRF040812: possible afterglow second Chandra observation
  48. GRB 040812: Second epoch CXO Observations
  49. GRB040823,optical observation
  50. XRF040812: GMRT observations
  51. XRF 040812: optical observation at VLT
  52. GRB 040812: Optical counterparts of CXO sources
  53. XRF040812: possible afterglow
  54. CXO observation of GRB 040812
  55. GRB 040812: radio observations
  56. GRB040812, optical/IR observations
  57. GRB 040812: a long GRB detected by INTEGRAL
  58. XRF040701: Optical Observations at ESO
  59. GRB 040730, infrared observations
  60. GRB 040730: a long GRB detected with INTEGRAL
  61. Ongoing activity of SGR 1806-20
  62. GRB040624: optical monitoring at TNG
  63. XRF 040701 - optical observations of the decaying Chandra source
  64. XRF040701: Second-Epoch Chandra Observations
  65. XRF040701: VLA Observations
  66. XRF040701: First-Epoch Chandra Observations
  67. GRB040624, optical observations
  68. GRB040706:observation at University of Miyazaki
  69. Optical Observations of GRB040624
  70. GRB 040624: optical observations at TNG and VLT
  71. MASTER: GRB 040624 optical observation after 0,48d
  72. GRB 040624, optical observations
  73. GRB 040624 - A long GRB detected with INTEGRAL
  74. GRB 030329: Rebrightening of hyperluminal ejecta.
  75. IPN Summary of SGR1806-20 Activity in 2004
  76. SGR 1806-20: no IR variability of the proposed counterparts
  77. MASTER:HETE Alert 3259 (SRG1806-20) optical observation
  78. SGR 1806-20, potential NIR counterpart
  79. GRB 040606: Optical observations
  80. MASTER: HETE Alert 3274 optical observation
  81. Activivty of SGR 1806-20
  82. GRB 040511, very fast decay?
  83. GRB 030324: Detection and Color of Host Galaxy
  84. GRB 040511: NIR observations with REM
  85. GRB040511: Candidate optical/NIR afterglow
  86. GRB 040511: ROTSE-III Rapid Optical Upper Limits
  87. GRB 040511: Second Epoch Optical Observations
  88. GRB 040511: Optical observations
  89. GRB 040511: Optical Observations
  90. GRB040511: Optical Observations
  91. GRB040511: Optical Observations
  92. Type Ic SN2001em (off-axis GRB jet?), optical spectrum
  93. GRB 040423 (=H3175): A Long GRB Localized by HETE
  94. GRB040422 : I-band follow-up observation at Lulin Observatory
  95. GRB 040422: ROTSE-IIIb Prompt Optical Limits
  96. GRB040422, BVRcIc field calibration
  97. GRB 040422,optical observation
  98. GRB 040422: a long GRB detected with INTEGRAL
  99. GRB 040403, deep optical observations
  100. MASTER: HETE Alert 3163, 3167 technical optical observation

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