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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"

20526 results found.

  1. GRB041006: RTT150 Optical Observations
  2. GRB 041016:Optical limit during first minute
  3. GRB041016: MASTER: Optical observations
  4. GRB 041015: Optical Observations at Rikubetsu
  5. GRB041006: Near Infrared observations
  6. GRB 041015 R band observations
  7. GRB041015: MASTER: Optical observations
  8. GRB041006: Fading X-ray Afterglow Observed with Chandra
  9. GRB 041006 R observations in Loiano
  10. GRB041006: VLT observations of the afterglow and host galaxy
  11. GRB041006: Optical observations and Potential host galaxy
  12. GRB 041006: SARA afterglow observations
  13. Search for SN light in XRF 040912 with MEGACAM
  14. GRB 040916: Afterglow Color at Early Times
  15. GRB 041006 Optical afterglow observations
  16. IBAS GRB Alert # 2010
  17. GRB 041006: BR observations with VATT
  18. GRB 041006: Redshift confirmed
  19. GRB041006: Liverpool Telescope optical observations
  20. GRB 041006: Colour measurement
  21. GRB 041006: Radio Observations
  22. GRB041006, further submilllimetre observations
  23. GRB041006: Optical photometry and spectroscopy at TNG
  24. GRB041006 (= H3570): Chandra Observations In Progress
  25. GRB041006, optical I observation
  26. GRB041006 (=HETE3570): optical observations
  27. ROTSE-IIIa Observations of GRB 041006
  28. GRB041006, submillimetre observations
  29. GRB041006: MASTER optical observations
  30. GRB 041006: Optical decay
  31. Very strong outburst from SGR 1806-20 detected with INTEGRAL
  32. XRF 020903: Observations of the Host Galaxy (authors)
  33. XRF 020903: Observations of the Host Galaxy
  34. SGR 1806-20 still active
  35. GRB 040924: Second Epoch WSRT Radio Observations
  36. radio observations, GRB 040924
  37. GRB040929: MASTER optical observations
  38. Konus-Wind and Helicon-Coronas-F observations of GRB040924
  39. GRB040924,optical observation
  40. GRB040924, RTT150 optical observation
  41. GRB040924, RTT150 optical observation
  42. GRB040924: KAIT observations
  43. GRB 040924: WSRT Radio Observations
  44. GRB040924 : Optical candidate observations at Lulin observatory
  45. GRB040924 : Optical candidate observations at Lulin observatory
  46. GRB040924: Optical afterglow properties
  47. GRB 040924: RTT150 optical observations
  48. GRB040924: MASTER Optical observations
  49. GRB040924 (H3564): Optical afterglow candidate
  50. XRF 040912: Radio Observations
  51. XRF 040916: Radio Observations
  52. XRF040916: continuing decay of OT
  53. TAROT Observations of GRB 040916 (HETE #3558)
  54. GRB040912(=H3557): Candidate Optical Afterglow
  55. XRF040916, optical observations
  56. XRF 040912, identification of CXO sources
  57. XRF040916, Ic observations
  58. XRF040916: optical follow-up observations
  59. GRB040916: Archival optical observations
  60. GRB040912(=H3557): Observations with the Chandra X-ray Observatory
  61. GRB040916: Optical observations
  62. ROTSE-IIIb Observations of GRB 040916 (HETE #3558)
  63. GRB040912 (= H3557): Chandra Observations Scheduled
  64. GRB 040912: Optical Observations
  65. GRB/XRF040912,optical observations
  66. GRB 040912, BVRI observations
  67. Optical observations of GRB/XRF 040912 = HETE 3557
  68. Optical observations of field of GRB040912
  69. HETE 3557: Optical observations
  70. GRB 040827 - Radio Observations
  71. GRB040825A: Optical observations
  72. GRB040825A: Optical observations
  73. GRB 040827: optical and NIR observations at the VLT
  74. GRB 040827: 2nd epoch of Magellan K-band imaging
  75. GRB 040827: Detection of NIR afterglow
  76. GRB 040827: Possible detection of optical afterglow
  77. GRB 040827: RTT150 optical observations
  78. GRB 040825B: Optical observations
  79. GRB040827 optical observations
  80. GRB 040825A,optical observations
  81. GRB040825A: optical observations
  82. GRB040825B: optical observations
  83. GRB040825B (=H3510): An XRF Localized in Real Time by HETE
  84. GRB 040825A: Optical observations.
  85. GRB040825B: Correction to GCN 2657
  86. GRB 040825: Optical observations
  87. GRB 040812: Second epoch CXO Observations
  88. XRF040812: GMRT observations
  89. XRF 040812: optical observation at VLT
  90. GRB 040812: Optical counterparts of CXO sources
  91. GRB 040812: Keck and LCO optical observations
  92. GRB 040812: Keck and LCO observations
  93. GRB 040812: radio observations
  94. GRB040812, optical/IR observations
  95. GRB 040810: Optical observations of a limited region
  96. XRF040701: Optical Observations at ESO
  97. GRB 040730, infrared observations
  98. GRB 040730: Optical observations
  99. GRB040624: optical monitoring at TNG
  100. XRF 040701 - optical observations of the decaying Chandra source

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