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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"

24890 results found.

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

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