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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"

24641 results found.

  1. GRB 040924: Subaru NIR observation
  2. XRF 040912: Radio Observations
  3. XRF 040916: Radio Observations
  4. GRB040912(=H3557): Chandra Candidate X-ray Afterglow
  5. XRF040916: continuing decay of OT
  6. TAROT Observations of GRB 040916 (HETE #3558)
  7. GRB040912(=H3557): Candidate Optical Afterglow
  8. XRF040916, optical observations
  9. XRF 040912, identification of CXO sources
  10. XRF040912, BVRcIc field calibration
  11. XRF040916, BVRcIc field calibration
  12. GRB040916: Archival optical observations
  13. GRB040912(=H3557): Observations with the Chandra X-ray Observatory
  14. GRB040916: Optical observations
  15. GRB040912 (= H3557): Chandra Observations Scheduled
  16. GRB 040912: Optical Observations
  17. GRB/XRF040912,optical observations
  18. GRB 040912, BVRI observations
  19. Optical observations of field of GRB040912
  20. HETE 3557: Optical observations
  21. GRB040903 - A XRF?
  22. GRB040827: analysis of the XMM-Newton observation
  23. GRB040903, REM near-IR observation
  24. Very bright burst detected from SGR 1806-20
  25. ROTSE-III Rapid Response to possible GRB 040903 (INTEGRAL #1972)
  26. Possible GRB 040903 - further analysis
  27. GRB 040827 - Radio Observations
  28. XMM-Newton Images of GRB 040827
  29. GRB 040827: optical and NIR observations at the VLT
  30. GRB 040827: UKIRT - 2nd epoch K-band imaging
  31. GRB 040827: 2nd epoch of Magellan K-band imaging
  32. GRB 040827: K imaging - no evidence of variability
  33. GRB 040827: Detection of NIR afterglow
  34. GRB040827 XMM-Newton observation
  35. GRB040825A: optical limit before GRB
  36. GRB 040825B: Optical observations
  37. GRB 040827 : Planned XMM-Newton observation
  38. GRB040825B, BVRcIc field photometry
  39. GRB040825A, BVRcIc field photometry
  40. GCN GRB OBSERBATION REPORT
  41. GRB 040825A,optical observations
  42. GRB040825A: optical observations
  43. GRB040825B: optical observations
  44. MASTER: GRB040825b optical observation
  45. GRB 040825: Optical observations
  46. XRF040812: possible afterglow second Chandra observation
  47. GRB 040812: Second epoch CXO Observations
  48. GRB040823,optical observation
  49. XRF040812: GMRT observations
  50. XRF 040812: optical observation at VLT
  51. GRB 040812: Optical counterparts of CXO sources
  52. XRF040812: possible afterglow
  53. CXO observation of GRB 040812
  54. GRB 040812: radio observations
  55. GRB040812, optical/IR observations
  56. GRB 040812: a long GRB detected by INTEGRAL
  57. XRF040701: Optical Observations at ESO
  58. GRB 040730, infrared observations
  59. GRB 040730: a long GRB detected with INTEGRAL
  60. Ongoing activity of SGR 1806-20
  61. GRB040624: optical monitoring at TNG
  62. XRF 040701 - optical observations of the decaying Chandra source
  63. XRF040701: Second-Epoch Chandra Observations
  64. XRF040701: VLA Observations
  65. XRF040701: First-Epoch Chandra Observations
  66. GRB040624, optical observations
  67. GRB040706:observation at University of Miyazaki
  68. Optical Observations of GRB040624
  69. GRB 040624: optical observations at TNG and VLT
  70. MASTER: GRB 040624 optical observation after 0,48d
  71. GRB 040624, optical observations
  72. GRB 040624 - A long GRB detected with INTEGRAL
  73. GRB 030329: Rebrightening of hyperluminal ejecta.
  74. IPN Summary of SGR1806-20 Activity in 2004
  75. SGR 1806-20: no IR variability of the proposed counterparts
  76. MASTER:HETE Alert 3259 (SRG1806-20) optical observation
  77. SGR 1806-20, potential NIR counterpart
  78. GRB 040606: Optical observations
  79. MASTER: HETE Alert 3274 optical observation
  80. Activivty of SGR 1806-20
  81. GRB 040511, very fast decay?
  82. GRB 030324: Detection and Color of Host Galaxy
  83. GRB 040511: NIR observations with REM
  84. GRB040511: Candidate optical/NIR afterglow
  85. GRB 040511: ROTSE-III Rapid Optical Upper Limits
  86. GRB 040511: Second Epoch Optical Observations
  87. GRB 040511: Optical observations
  88. GRB 040511: Optical Observations
  89. GRB040511: Optical Observations
  90. GRB040511: Optical Observations
  91. Type Ic SN2001em (off-axis GRB jet?), optical spectrum
  92. GRB 040423 (=H3175): A Long GRB Localized by HETE
  93. GRB040422 : I-band follow-up observation at Lulin Observatory
  94. GRB 040422: ROTSE-IIIb Prompt Optical Limits
  95. GRB040422, BVRcIc field calibration
  96. GRB 040422,optical observation
  97. GRB 040422: a long GRB detected with INTEGRAL
  98. GRB 040403, deep optical observations
  99. MASTER: HETE Alert 3163, 3167 technical optical observation
  100. HETE/IPN localization of GRB040403A (=H3143, a long burst) and GRB040403B(=H3144, a short/hard burst)

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