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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"

28081 results found.

  1. GRB 041016: Optical limits
  2. GRB 041016:Optical limit during first minute
  3. GRB 041015: Optical Observations at Rikubetsu
  4. GRB 041016: Optical limit
  5. GRB 041015 R band observations
  6. GRB040924, BVRcIc field calibration
  7. GRB041015,optical observation
  8. GRB041006: Fading X-ray Afterglow Observed with Chandra
  9. GRB 041015 - A long GRB detected by INTEGRAL
  10. GRB041006: VLT observations of the afterglow and host galaxy
  11. GRB041006: Optical observations and Potential host galaxy
  12. GRB041006, BVRcIc field calibration
  13. GRB 040924: VLT spectroscopy
  14. GRB 041006: SARA afterglow observations
  15. GRB041006, optical observation in CrAO
  16. Search for SN light in XRF 040912 with MEGACAM
  17. GRB 041006: BR observations with VATT
  18. GRB 041006: Redshift confirmed
  19. GRB 041006: Radio Observations
  20. GRB 041006 : optical follow-up observation at Lulin Observatory
  21. GRB041006: Optical photometry and spectroscopy at TNG
  22. GRB 041006: presice astrometry
  23. GRB041006, optical I observation
  24. GRB041006 (=HETE3570): optical observations
  25. ROTSE-IIIa Observations of GRB 041006
  26. GRB041006: MASTER optical observations
  27. GRB041006,optical observation
  28. Konus-Wind observation of a series SGR 1806-20 bursts on 041005
  29. GRB041006: Fading of optical afterglow candidate
  30. GRB 041006: Optical afterglow candidate
  31. Bursts from SGR 1806-20: Preliminary INTEGRAL results
  32. XRF 020903: Observations of the Host Galaxy
  33. radio observations, GRB 040924
  34. GRB040929,optical observation
  35. GRB040924,optical observation
  36. GRB040924,optical observation
  37. GRB 040924: detection of possible host galaxy by Subaru
  38. GRB040924: KAIT observations
  39. GRB040924 : Optical candidate observations at Lulin observatory
  40. GRB040924 : Optical candidate observations at Lulin observatory
  41. GRB 040924: Subaru NIR observation
  42. XRF 040912: Radio Observations
  43. XRF 040916: Radio Observations
  44. GRB040912(=H3557): Chandra Candidate X-ray Afterglow
  45. XRF040916: continuing decay of OT
  46. TAROT Observations of GRB 040916 (HETE #3558)
  47. GRB040912(=H3557): Candidate Optical Afterglow
  48. XRF040916, optical observations
  49. XRF 040912, identification of CXO sources
  50. XRF040912, BVRcIc field calibration
  51. XRF040916, BVRcIc field calibration
  52. GRB040916: Archival optical observations
  53. GRB040912(=H3557): Observations with the Chandra X-ray Observatory
  54. GRB040916: Optical observations
  55. GRB040912 (= H3557): Chandra Observations Scheduled
  56. GRB 040912: Optical Observations
  57. GRB/XRF040912,optical observations
  58. GRB 040912, BVRI observations
  59. Optical observations of field of GRB040912
  60. HETE 3557: Optical observations
  61. GRB040903 - A XRF?
  62. GRB040827: analysis of the XMM-Newton observation
  63. GRB040903, REM near-IR observation
  64. Very bright burst detected from SGR 1806-20
  65. ROTSE-III Rapid Response to possible GRB 040903 (INTEGRAL #1972)
  66. Possible GRB 040903 - further analysis
  67. GRB 040827 - Radio Observations
  68. XMM-Newton Images of GRB 040827
  69. GRB 040827: optical and NIR observations at the VLT
  70. GRB 040827: UKIRT - 2nd epoch K-band imaging
  71. GRB 040827: 2nd epoch of Magellan K-band imaging
  72. GRB 040827: K imaging - no evidence of variability
  73. GRB 040827: Detection of NIR afterglow
  74. GRB040827 XMM-Newton observation
  75. GRB040825A: optical limit before GRB
  76. GRB 040825B: Optical observations
  77. GRB 040827 : Planned XMM-Newton observation
  78. GRB040825B, BVRcIc field photometry
  79. GRB040825A, BVRcIc field photometry
  80. GCN GRB OBSERBATION REPORT
  81. GRB 040825A,optical observations
  82. GRB040825A: optical observations
  83. GRB040825B: optical observations
  84. MASTER: GRB040825b optical observation
  85. GRB 040825: Optical observations
  86. XRF040812: possible afterglow second Chandra observation
  87. GRB 040812: Second epoch CXO Observations
  88. GRB040823,optical observation
  89. XRF040812: GMRT observations
  90. XRF 040812: optical observation at VLT
  91. GRB 040812: Optical counterparts of CXO sources
  92. XRF040812: possible afterglow
  93. CXO observation of GRB 040812
  94. GRB 040812: radio observations
  95. GRB040812, optical/IR observations
  96. GRB 040812: a long GRB detected by INTEGRAL
  97. XRF040701: Optical Observations at ESO
  98. GRB 040730, infrared observations
  99. GRB 040730: a long GRB detected with INTEGRAL
  100. Ongoing activity of SGR 1806-20

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