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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"

25043 results found.

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

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