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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"

24874 results found.

  1. GRB041006: Fading X-ray Afterglow Observed with Chandra
  2. GRB 041015 - A long GRB detected by INTEGRAL
  3. GRB041006: VLT observations of the afterglow and host galaxy
  4. GRB041006: Optical observations and Potential host galaxy
  5. GRB041006, BVRcIc field calibration
  6. GRB 040924: VLT spectroscopy
  7. GRB 041006: SARA afterglow observations
  8. GRB041006, optical observation in CrAO
  9. Search for SN light in XRF 040912 with MEGACAM
  10. GRB 041006: BR observations with VATT
  11. GRB 041006: Redshift confirmed
  12. GRB 041006: Radio Observations
  13. GRB 041006 : optical follow-up observation at Lulin Observatory
  14. GRB041006: Optical photometry and spectroscopy at TNG
  15. GRB 041006: presice astrometry
  16. GRB041006, optical I observation
  17. GRB041006 (=HETE3570): optical observations
  18. ROTSE-IIIa Observations of GRB 041006
  19. GRB041006: MASTER optical observations
  20. GRB041006,optical observation
  21. Konus-Wind observation of a series SGR 1806-20 bursts on 041005
  22. GRB041006: Fading of optical afterglow candidate
  23. GRB 041006: Optical afterglow candidate
  24. Bursts from SGR 1806-20: Preliminary INTEGRAL results
  25. XRF 020903: Observations of the Host Galaxy
  26. radio observations, GRB 040924
  27. GRB040929,optical observation
  28. GRB040924,optical observation
  29. GRB040924,optical observation
  30. GRB 040924: detection of possible host galaxy by Subaru
  31. GRB040924: KAIT observations
  32. GRB040924 : Optical candidate observations at Lulin observatory
  33. GRB040924 : Optical candidate observations at Lulin observatory
  34. GRB 040924: Subaru NIR observation
  35. XRF 040912: Radio Observations
  36. XRF 040916: Radio Observations
  37. GRB040912(=H3557): Chandra Candidate X-ray Afterglow
  38. XRF040916: continuing decay of OT
  39. TAROT Observations of GRB 040916 (HETE #3558)
  40. GRB040912(=H3557): Candidate Optical Afterglow
  41. XRF040916, optical observations
  42. XRF 040912, identification of CXO sources
  43. XRF040912, BVRcIc field calibration
  44. XRF040916, BVRcIc field calibration
  45. GRB040916: Archival optical observations
  46. GRB040912(=H3557): Observations with the Chandra X-ray Observatory
  47. GRB040916: Optical observations
  48. GRB040912 (= H3557): Chandra Observations Scheduled
  49. GRB 040912: Optical Observations
  50. GRB/XRF040912,optical observations
  51. GRB 040912, BVRI observations
  52. Optical observations of field of GRB040912
  53. HETE 3557: Optical observations
  54. GRB040903 - A XRF?
  55. GRB040827: analysis of the XMM-Newton observation
  56. GRB040903, REM near-IR observation
  57. Very bright burst detected from SGR 1806-20
  58. ROTSE-III Rapid Response to possible GRB 040903 (INTEGRAL #1972)
  59. Possible GRB 040903 - further analysis
  60. GRB 040827 - Radio Observations
  61. XMM-Newton Images of GRB 040827
  62. GRB 040827: optical and NIR observations at the VLT
  63. GRB 040827: UKIRT - 2nd epoch K-band imaging
  64. GRB 040827: 2nd epoch of Magellan K-band imaging
  65. GRB 040827: K imaging - no evidence of variability
  66. GRB 040827: Detection of NIR afterglow
  67. GRB040827 XMM-Newton observation
  68. GRB040825A: optical limit before GRB
  69. GRB 040825B: Optical observations
  70. GRB 040827 : Planned XMM-Newton observation
  71. GRB040825B, BVRcIc field photometry
  72. GRB040825A, BVRcIc field photometry
  73. GCN GRB OBSERBATION REPORT
  74. GRB 040825A,optical observations
  75. GRB040825A: optical observations
  76. GRB040825B: optical observations
  77. MASTER: GRB040825b optical observation
  78. GRB 040825: Optical observations
  79. XRF040812: possible afterglow second Chandra observation
  80. GRB 040812: Second epoch CXO Observations
  81. GRB040823,optical observation
  82. XRF040812: GMRT observations
  83. XRF 040812: optical observation at VLT
  84. GRB 040812: Optical counterparts of CXO sources
  85. XRF040812: possible afterglow
  86. CXO observation of GRB 040812
  87. GRB 040812: radio observations
  88. GRB040812, optical/IR observations
  89. GRB 040812: a long GRB detected by INTEGRAL
  90. XRF040701: Optical Observations at ESO
  91. GRB 040730, infrared observations
  92. GRB 040730: a long GRB detected with INTEGRAL
  93. Ongoing activity of SGR 1806-20
  94. GRB040624: optical monitoring at TNG
  95. XRF 040701 - optical observations of the decaying Chandra source
  96. XRF040701: Second-Epoch Chandra Observations
  97. XRF040701: VLA Observations
  98. XRF040701: First-Epoch Chandra Observations
  99. GRB040624, optical observations
  100. GRB040706:observation at University of Miyazaki

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