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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"

28086 results found.

  1. HST Observations: XRF 040701 and 040812
  2. Bright bursts from SGR1806-20
  3. GRB 041016: BOOTES-2 simultaneous observation
  4. GRB041006: RTT150 Optical Observations
  5. GRB041016,optical observation
  6. GRB 041016: Optical limits
  7. GRB 041016:Optical limit during first minute
  8. GRB 041015: Optical Observations at Rikubetsu
  9. GRB 041016: Optical limit
  10. GRB 041015 R band observations
  11. GRB040924, BVRcIc field calibration
  12. GRB041015,optical observation
  13. GRB041006: Fading X-ray Afterglow Observed with Chandra
  14. GRB 041015 - A long GRB detected by INTEGRAL
  15. GRB041006: VLT observations of the afterglow and host galaxy
  16. GRB041006: Optical observations and Potential host galaxy
  17. GRB041006, BVRcIc field calibration
  18. GRB 040924: VLT spectroscopy
  19. GRB 041006: SARA afterglow observations
  20. GRB041006, optical observation in CrAO
  21. Search for SN light in XRF 040912 with MEGACAM
  22. GRB 041006: BR observations with VATT
  23. GRB 041006: Redshift confirmed
  24. GRB 041006: Radio Observations
  25. GRB 041006 : optical follow-up observation at Lulin Observatory
  26. GRB041006: Optical photometry and spectroscopy at TNG
  27. GRB 041006: presice astrometry
  28. GRB041006, optical I observation
  29. GRB041006 (=HETE3570): optical observations
  30. ROTSE-IIIa Observations of GRB 041006
  31. GRB041006: MASTER optical observations
  32. GRB041006,optical observation
  33. Konus-Wind observation of a series SGR 1806-20 bursts on 041005
  34. GRB041006: Fading of optical afterglow candidate
  35. GRB 041006: Optical afterglow candidate
  36. Bursts from SGR 1806-20: Preliminary INTEGRAL results
  37. XRF 020903: Observations of the Host Galaxy
  38. radio observations, GRB 040924
  39. GRB040929,optical observation
  40. GRB040924,optical observation
  41. GRB040924,optical observation
  42. GRB 040924: detection of possible host galaxy by Subaru
  43. GRB040924: KAIT observations
  44. GRB040924 : Optical candidate observations at Lulin observatory
  45. GRB040924 : Optical candidate observations at Lulin observatory
  46. GRB 040924: Subaru NIR observation
  47. XRF 040912: Radio Observations
  48. XRF 040916: Radio Observations
  49. GRB040912(=H3557): Chandra Candidate X-ray Afterglow
  50. XRF040916: continuing decay of OT
  51. TAROT Observations of GRB 040916 (HETE #3558)
  52. GRB040912(=H3557): Candidate Optical Afterglow
  53. XRF040916, optical observations
  54. XRF 040912, identification of CXO sources
  55. XRF040912, BVRcIc field calibration
  56. XRF040916, BVRcIc field calibration
  57. GRB040916: Archival optical observations
  58. GRB040912(=H3557): Observations with the Chandra X-ray Observatory
  59. GRB040916: Optical observations
  60. GRB040912 (= H3557): Chandra Observations Scheduled
  61. GRB 040912: Optical Observations
  62. GRB/XRF040912,optical observations
  63. GRB 040912, BVRI observations
  64. Optical observations of field of GRB040912
  65. HETE 3557: Optical observations
  66. GRB040903 - A XRF?
  67. GRB040827: analysis of the XMM-Newton observation
  68. GRB040903, REM near-IR observation
  69. Very bright burst detected from SGR 1806-20
  70. ROTSE-III Rapid Response to possible GRB 040903 (INTEGRAL #1972)
  71. Possible GRB 040903 - further analysis
  72. GRB 040827 - Radio Observations
  73. XMM-Newton Images of GRB 040827
  74. GRB 040827: optical and NIR observations at the VLT
  75. GRB 040827: UKIRT - 2nd epoch K-band imaging
  76. GRB 040827: 2nd epoch of Magellan K-band imaging
  77. GRB 040827: K imaging - no evidence of variability
  78. GRB 040827: Detection of NIR afterglow
  79. GRB040827 XMM-Newton observation
  80. GRB040825A: optical limit before GRB
  81. GRB 040825B: Optical observations
  82. GRB 040827 : Planned XMM-Newton observation
  83. GRB040825B, BVRcIc field photometry
  84. GRB040825A, BVRcIc field photometry
  85. GCN GRB OBSERBATION REPORT
  86. GRB 040825A,optical observations
  87. GRB040825A: optical observations
  88. GRB040825B: optical observations
  89. MASTER: GRB040825b optical observation
  90. GRB 040825: Optical observations
  91. XRF040812: possible afterglow second Chandra observation
  92. GRB 040812: Second epoch CXO Observations
  93. GRB040823,optical observation
  94. XRF040812: GMRT observations
  95. XRF 040812: optical observation at VLT
  96. GRB 040812: Optical counterparts of CXO sources
  97. XRF040812: possible afterglow
  98. CXO observation of GRB 040812
  99. GRB 040812: radio observations
  100. GRB040812, optical/IR observations

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