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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"

24683 results found.

  1. GRB041006: RTT150 Optical Observations
  2. GRB041016,optical observation
  3. GRB 041016: Optical limits
  4. GRB 041016:Optical limit during first minute
  5. GRB 041015: Optical Observations at Rikubetsu
  6. GRB 041016: Optical limit
  7. GRB 041015 R band observations
  8. GRB040924, BVRcIc field calibration
  9. GRB041015,optical observation
  10. GRB041006: Fading X-ray Afterglow Observed with Chandra
  11. GRB 041015 - A long GRB detected by INTEGRAL
  12. GRB041006: VLT observations of the afterglow and host galaxy
  13. GRB041006: Optical observations and Potential host galaxy
  14. GRB041006, BVRcIc field calibration
  15. GRB 040924: VLT spectroscopy
  16. GRB 041006: SARA afterglow observations
  17. GRB041006, optical observation in CrAO
  18. Search for SN light in XRF 040912 with MEGACAM
  19. GRB 041006: BR observations with VATT
  20. GRB 041006: Redshift confirmed
  21. GRB 041006: Radio Observations
  22. GRB 041006 : optical follow-up observation at Lulin Observatory
  23. GRB041006: Optical photometry and spectroscopy at TNG
  24. GRB 041006: presice astrometry
  25. GRB041006, optical I observation
  26. GRB041006 (=HETE3570): optical observations
  27. ROTSE-IIIa Observations of GRB 041006
  28. GRB041006: MASTER optical observations
  29. GRB041006,optical observation
  30. Konus-Wind observation of a series SGR 1806-20 bursts on 041005
  31. GRB041006: Fading of optical afterglow candidate
  32. GRB 041006: Optical afterglow candidate
  33. Bursts from SGR 1806-20: Preliminary INTEGRAL results
  34. XRF 020903: Observations of the Host Galaxy
  35. radio observations, GRB 040924
  36. GRB040929,optical observation
  37. GRB040924,optical observation
  38. GRB040924,optical observation
  39. GRB 040924: detection of possible host galaxy by Subaru
  40. GRB040924: KAIT observations
  41. GRB040924 : Optical candidate observations at Lulin observatory
  42. GRB040924 : Optical candidate observations at Lulin observatory
  43. GRB 040924: Subaru NIR observation
  44. XRF 040912: Radio Observations
  45. XRF 040916: Radio Observations
  46. GRB040912(=H3557): Chandra Candidate X-ray Afterglow
  47. XRF040916: continuing decay of OT
  48. TAROT Observations of GRB 040916 (HETE #3558)
  49. GRB040912(=H3557): Candidate Optical Afterglow
  50. XRF040916, optical observations
  51. XRF 040912, identification of CXO sources
  52. XRF040912, BVRcIc field calibration
  53. XRF040916, BVRcIc field calibration
  54. GRB040916: Archival optical observations
  55. GRB040912(=H3557): Observations with the Chandra X-ray Observatory
  56. GRB040916: Optical observations
  57. GRB040912 (= H3557): Chandra Observations Scheduled
  58. GRB 040912: Optical Observations
  59. GRB/XRF040912,optical observations
  60. GRB 040912, BVRI observations
  61. Optical observations of field of GRB040912
  62. HETE 3557: Optical observations
  63. GRB040903 - A XRF?
  64. GRB040827: analysis of the XMM-Newton observation
  65. GRB040903, REM near-IR observation
  66. Very bright burst detected from SGR 1806-20
  67. ROTSE-III Rapid Response to possible GRB 040903 (INTEGRAL #1972)
  68. Possible GRB 040903 - further analysis
  69. GRB 040827 - Radio Observations
  70. XMM-Newton Images of GRB 040827
  71. GRB 040827: optical and NIR observations at the VLT
  72. GRB 040827: UKIRT - 2nd epoch K-band imaging
  73. GRB 040827: 2nd epoch of Magellan K-band imaging
  74. GRB 040827: K imaging - no evidence of variability
  75. GRB 040827: Detection of NIR afterglow
  76. GRB040827 XMM-Newton observation
  77. GRB040825A: optical limit before GRB
  78. GRB 040825B: Optical observations
  79. GRB 040827 : Planned XMM-Newton observation
  80. GRB040825B, BVRcIc field photometry
  81. GRB040825A, BVRcIc field photometry
  82. GCN GRB OBSERBATION REPORT
  83. GRB 040825A,optical observations
  84. GRB040825A: optical observations
  85. GRB040825B: optical observations
  86. MASTER: GRB040825b optical observation
  87. GRB 040825: Optical observations
  88. XRF040812: possible afterglow second Chandra observation
  89. GRB 040812: Second epoch CXO Observations
  90. GRB040823,optical observation
  91. XRF040812: GMRT observations
  92. XRF 040812: optical observation at VLT
  93. GRB 040812: Optical counterparts of CXO sources
  94. XRF040812: possible afterglow
  95. CXO observation of GRB 040812
  96. GRB 040812: radio observations
  97. GRB040812, optical/IR observations
  98. GRB 040812: a long GRB detected by INTEGRAL
  99. XRF040701: Optical Observations at ESO
  100. GRB 040730, infrared observations

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