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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"

27391 results found.

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

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