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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"

26944 results found.

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

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