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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"

27392 results found.

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

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