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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"

26366 results found.

  1. Search for SN light in XRF 040912 with MEGACAM
  2. GRB 041006: BR observations with VATT
  3. GRB 041006: Redshift confirmed
  4. GRB 041006: Radio Observations
  5. GRB 041006 : optical follow-up observation at Lulin Observatory
  6. GRB041006: Optical photometry and spectroscopy at TNG
  7. GRB 041006: presice astrometry
  8. GRB041006, optical I observation
  9. GRB041006 (=HETE3570): optical observations
  10. ROTSE-IIIa Observations of GRB 041006
  11. GRB041006: MASTER optical observations
  12. GRB041006,optical observation
  13. Konus-Wind observation of a series SGR 1806-20 bursts on 041005
  14. GRB041006: Fading of optical afterglow candidate
  15. GRB 041006: Optical afterglow candidate
  16. Bursts from SGR 1806-20: Preliminary INTEGRAL results
  17. XRF 020903: Observations of the Host Galaxy
  18. radio observations, GRB 040924
  19. GRB040929,optical observation
  20. GRB040924,optical observation
  21. GRB040924,optical observation
  22. GRB 040924: detection of possible host galaxy by Subaru
  23. GRB040924: KAIT observations
  24. GRB040924 : Optical candidate observations at Lulin observatory
  25. GRB040924 : Optical candidate observations at Lulin observatory
  26. GRB 040924: Subaru NIR observation
  27. XRF 040912: Radio Observations
  28. XRF 040916: Radio Observations
  29. GRB040912(=H3557): Chandra Candidate X-ray Afterglow
  30. XRF040916: continuing decay of OT
  31. TAROT Observations of GRB 040916 (HETE #3558)
  32. GRB040912(=H3557): Candidate Optical Afterglow
  33. XRF040916, optical observations
  34. XRF 040912, identification of CXO sources
  35. XRF040912, BVRcIc field calibration
  36. XRF040916, BVRcIc field calibration
  37. GRB040916: Archival optical observations
  38. GRB040912(=H3557): Observations with the Chandra X-ray Observatory
  39. GRB040916: Optical observations
  40. GRB040912 (= H3557): Chandra Observations Scheduled
  41. GRB 040912: Optical Observations
  42. GRB/XRF040912,optical observations
  43. GRB 040912, BVRI observations
  44. Optical observations of field of GRB040912
  45. HETE 3557: Optical observations
  46. GRB040903 - A XRF?
  47. GRB040827: analysis of the XMM-Newton observation
  48. GRB040903, REM near-IR observation
  49. Very bright burst detected from SGR 1806-20
  50. ROTSE-III Rapid Response to possible GRB 040903 (INTEGRAL #1972)
  51. Possible GRB 040903 - further analysis
  52. GRB 040827 - Radio Observations
  53. XMM-Newton Images of GRB 040827
  54. GRB 040827: optical and NIR observations at the VLT
  55. GRB 040827: UKIRT - 2nd epoch K-band imaging
  56. GRB 040827: 2nd epoch of Magellan K-band imaging
  57. GRB 040827: K imaging - no evidence of variability
  58. GRB 040827: Detection of NIR afterglow
  59. GRB040827 XMM-Newton observation
  60. GRB040825A: optical limit before GRB
  61. GRB 040825B: Optical observations
  62. GRB 040827 : Planned XMM-Newton observation
  63. GRB040825B, BVRcIc field photometry
  64. GRB040825A, BVRcIc field photometry
  65. GCN GRB OBSERBATION REPORT
  66. GRB 040825A,optical observations
  67. GRB040825A: optical observations
  68. GRB040825B: optical observations
  69. MASTER: GRB040825b optical observation
  70. GRB 040825: Optical observations
  71. XRF040812: possible afterglow second Chandra observation
  72. GRB 040812: Second epoch CXO Observations
  73. GRB040823,optical observation
  74. XRF040812: GMRT observations
  75. XRF 040812: optical observation at VLT
  76. GRB 040812: Optical counterparts of CXO sources
  77. XRF040812: possible afterglow
  78. CXO observation of GRB 040812
  79. GRB 040812: radio observations
  80. GRB040812, optical/IR observations
  81. GRB 040812: a long GRB detected by INTEGRAL
  82. XRF040701: Optical Observations at ESO
  83. GRB 040730, infrared observations
  84. GRB 040730: a long GRB detected with INTEGRAL
  85. Ongoing activity of SGR 1806-20
  86. GRB040624: optical monitoring at TNG
  87. XRF 040701 - optical observations of the decaying Chandra source
  88. XRF040701: Second-Epoch Chandra Observations
  89. XRF040701: VLA Observations
  90. XRF040701: First-Epoch Chandra Observations
  91. GRB040624, optical observations
  92. GRB040706:observation at University of Miyazaki
  93. Optical Observations of GRB040624
  94. GRB 040624: optical observations at TNG and VLT
  95. MASTER: GRB 040624 optical observation after 0,48d
  96. GRB 040624, optical observations
  97. GRB 040624 - A long GRB detected with INTEGRAL
  98. GRB 030329: Rebrightening of hyperluminal ejecta.
  99. IPN Summary of SGR1806-20 Activity in 2004
  100. SGR 1806-20: no IR variability of the proposed counterparts

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