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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"

24887 results found.

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

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