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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"

21820 results found.

  1. GRB041217: P60 Optical Observations
  2. GRB041217: Infrared Observations
  3. GRB041211: Faulkes Telescope continued optical monitoring
  4. Optical transient (GRB?) in Lynx
  5. Optical transient (GRB?) in Lynx, UT Dec 11.4436
  6. GRB041211: Continued P60 Observations
  7. GRB041211: RAPTOR observations
  8. GRB041211, Faulkes Telescope optical observation
  9. GRB 041211: Infrared Observations
  10. GRB 041211: KAIT observations
  11. GRB 041211: Optical follow-up in East Asian region
  12. GRB970815: Discovery of Optical Afterglow
  13. GRB041015: Near-Infrared observations
  14. GRB 040924: Afterglow Color
  15. GRB 041006: Optical Observations
  16. GRB041006, late-time optical photometry
  17. GRB041006: RTT150 Optical Observations
  18. GRB041015 : Multi epoch optical observations
  19. HST Observations: XRF 040701 and 040812
  20. GRB041006: RTT150 Optical Observations
  21. GRB 041016:Optical limit during first minute
  22. GRB041016: MASTER: Optical observations
  23. GRB 041015: Optical Observations at Rikubetsu
  24. GRB041006: Near Infrared observations
  25. GRB 041015 R band observations
  26. GRB041015: MASTER: Optical observations
  27. GRB041006: Fading X-ray Afterglow Observed with Chandra
  28. GRB 041006 R observations in Loiano
  29. GRB041006: VLT observations of the afterglow and host galaxy
  30. GRB041006: Optical observations and Potential host galaxy
  31. GRB 040924: VLT spectroscopy
  32. GRB 041006: SARA afterglow observations
  33. Search for SN light in XRF 040912 with MEGACAM
  34. GRB 040916: Afterglow Color at Early Times
  35. GRB 041006 Optical afterglow observations
  36. IBAS GRB Alert # 2010
  37. GRB 041006: BR observations with VATT
  38. GRB 041006: Redshift confirmed
  39. GRB041006: Liverpool Telescope optical observations
  40. GRB 041006: Colour measurement
  41. GRB 041006: Radio Observations
  42. GRB041006, further submilllimetre observations
  43. GRB041006: Optical photometry and spectroscopy at TNG
  44. GRB041006 (= H3570): Chandra Observations In Progress
  45. GRB041006, optical I observation
  46. GRB041006 (=HETE3570): optical observations
  47. ROTSE-IIIa Observations of GRB 041006
  48. GRB041006, submillimetre observations
  49. GRB041006: MASTER optical observations
  50. GRB 041006: Optical decay
  51. Very strong outburst from SGR 1806-20 detected with INTEGRAL
  52. XRF 020903: Observations of the Host Galaxy (authors)
  53. XRF 020903: Observations of the Host Galaxy
  54. SGR 1806-20 still active
  55. GRB 040924: Second Epoch WSRT Radio Observations
  56. radio observations, GRB 040924
  57. GRB040929: MASTER optical observations
  58. Konus-Wind and Helicon-Coronas-F observations of GRB040924
  59. GRB040924,optical observation
  60. GRB040924, RTT150 optical observation
  61. GRB 040924: detection of possible host galaxy by Subaru
  62. GRB040924, RTT150 optical observation
  63. GRB040924: KAIT observations
  64. GRB 040924: WSRT Radio Observations
  65. GRB040924 : Optical candidate observations at Lulin observatory
  66. GRB040924 : Optical candidate observations at Lulin observatory
  67. GRB040924: Optical afterglow properties
  68. GRB 040924: RTT150 optical observations
  69. GRB040924: MASTER Optical observations
  70. GRB040924 (H3564): Optical afterglow candidate
  71. XRF 040912: Radio Observations
  72. XRF 040916: Radio Observations
  73. GRB040912(=H3557): Chandra Candidate X-ray Afterglow
  74. XRF040916: continuing decay of OT
  75. TAROT Observations of GRB 040916 (HETE #3558)
  76. XRF040916, optical observations
  77. XRF 040912, identification of CXO sources
  78. XRF040916, Ic observations
  79. XRF040916: optical follow-up observations
  80. GRB040916: Archival optical observations
  81. GRB040912(=H3557): Observations with the Chandra X-ray Observatory
  82. GRB040916: Optical observations
  83. ROTSE-IIIb Observations of GRB 040916 (HETE #3558)
  84. GRB040912 (= H3557): Chandra Observations Scheduled
  85. GRB 040912: Optical Observations
  86. GRB/XRF040912,optical observations
  87. GRB 040912, BVRI observations
  88. Optical observations of GRB/XRF 040912 = HETE 3557
  89. Optical observations of field of GRB040912
  90. HETE 3557: Optical observations
  91. GRB040827: analysis of the XMM-Newton observation
  92. GRB 040827 - Radio Observations
  93. GRB040825A: Optical observations
  94. GRB040825A: Optical observations
  95. GRB 040827: optical and NIR observations at the VLT
  96. GRB 040827: 2nd epoch of Magellan K-band imaging
  97. GRB 040827: Possible detection of optical afterglow
  98. GRB 040827: RTT150 optical observations
  99. GRB 040825B: Optical observations
  100. GRB040827 optical observations

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