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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"

28053 results found.

  1. GRB041006: Fading of optical afterglow candidate
  2. GRB 041006: Optical afterglow candidate
  3. Bursts from SGR 1806-20: Preliminary INTEGRAL results
  4. XRF 020903: Observations of the Host Galaxy
  5. radio observations, GRB 040924
  6. GRB040929,optical observation
  7. GRB040924,optical observation
  8. GRB040924,optical observation
  9. GRB 040924: detection of possible host galaxy by Subaru
  10. GRB040924: KAIT observations
  11. GRB040924 : Optical candidate observations at Lulin observatory
  12. GRB040924 : Optical candidate observations at Lulin observatory
  13. GRB 040924: Subaru NIR observation
  14. XRF 040912: Radio Observations
  15. XRF 040916: Radio Observations
  16. GRB040912(=H3557): Chandra Candidate X-ray Afterglow
  17. XRF040916: continuing decay of OT
  18. TAROT Observations of GRB 040916 (HETE #3558)
  19. GRB040912(=H3557): Candidate Optical Afterglow
  20. XRF040916, optical observations
  21. XRF 040912, identification of CXO sources
  22. XRF040912, BVRcIc field calibration
  23. XRF040916, BVRcIc field calibration
  24. GRB040916: Archival optical observations
  25. GRB040912(=H3557): Observations with the Chandra X-ray Observatory
  26. GRB040916: Optical observations
  27. GRB040912 (= H3557): Chandra Observations Scheduled
  28. GRB 040912: Optical Observations
  29. GRB/XRF040912,optical observations
  30. GRB 040912, BVRI observations
  31. Optical observations of field of GRB040912
  32. HETE 3557: Optical observations
  33. GRB040903 - A XRF?
  34. GRB040827: analysis of the XMM-Newton observation
  35. GRB040903, REM near-IR observation
  36. Very bright burst detected from SGR 1806-20
  37. ROTSE-III Rapid Response to possible GRB 040903 (INTEGRAL #1972)
  38. Possible GRB 040903 - further analysis
  39. GRB 040827 - Radio Observations
  40. XMM-Newton Images of GRB 040827
  41. GRB 040827: optical and NIR observations at the VLT
  42. GRB 040827: UKIRT - 2nd epoch K-band imaging
  43. GRB 040827: 2nd epoch of Magellan K-band imaging
  44. GRB 040827: K imaging - no evidence of variability
  45. GRB 040827: Detection of NIR afterglow
  46. GRB040827 XMM-Newton observation
  47. GRB040825A: optical limit before GRB
  48. GRB 040825B: Optical observations
  49. GRB 040827 : Planned XMM-Newton observation
  50. GRB040825B, BVRcIc field photometry
  51. GRB040825A, BVRcIc field photometry
  52. GCN GRB OBSERBATION REPORT
  53. GRB 040825A,optical observations
  54. GRB040825A: optical observations
  55. GRB040825B: optical observations
  56. MASTER: GRB040825b optical observation
  57. GRB 040825: Optical observations
  58. XRF040812: possible afterglow second Chandra observation
  59. GRB 040812: Second epoch CXO Observations
  60. GRB040823,optical observation
  61. XRF040812: GMRT observations
  62. XRF 040812: optical observation at VLT
  63. GRB 040812: Optical counterparts of CXO sources
  64. XRF040812: possible afterglow
  65. CXO observation of GRB 040812
  66. GRB 040812: radio observations
  67. GRB040812, optical/IR observations
  68. GRB 040812: a long GRB detected by INTEGRAL
  69. XRF040701: Optical Observations at ESO
  70. GRB 040730, infrared observations
  71. GRB 040730: a long GRB detected with INTEGRAL
  72. Ongoing activity of SGR 1806-20
  73. GRB040624: optical monitoring at TNG
  74. XRF 040701 - optical observations of the decaying Chandra source
  75. XRF040701: Second-Epoch Chandra Observations
  76. XRF040701: VLA Observations
  77. XRF040701: First-Epoch Chandra Observations
  78. GRB040624, optical observations
  79. GRB040706:observation at University of Miyazaki
  80. Optical Observations of GRB040624
  81. GRB 040624: optical observations at TNG and VLT
  82. MASTER: GRB 040624 optical observation after 0,48d
  83. GRB 040624, optical observations
  84. GRB 040624 - A long GRB detected with INTEGRAL
  85. GRB 030329: Rebrightening of hyperluminal ejecta.
  86. IPN Summary of SGR1806-20 Activity in 2004
  87. SGR 1806-20: no IR variability of the proposed counterparts
  88. MASTER:HETE Alert 3259 (SRG1806-20) optical observation
  89. SGR 1806-20, potential NIR counterpart
  90. GRB 040606: Optical observations
  91. MASTER: HETE Alert 3274 optical observation
  92. Activivty of SGR 1806-20
  93. GRB 040511, very fast decay?
  94. GRB 030324: Detection and Color of Host Galaxy
  95. GRB 040511: NIR observations with REM
  96. GRB040511: Candidate optical/NIR afterglow
  97. GRB 040511: ROTSE-III Rapid Optical Upper Limits
  98. GRB 040511: Second Epoch Optical Observations
  99. GRB 040511: Optical observations
  100. GRB 040511: Optical Observations

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