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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').
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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"

28077 results found.

  1. GRB 020625, optical observations
  2. GRB 020625: Optical observations
  3. GRB 020531: optical photometry of Chandra sources
  4. HETE #2081: Optical observations
  5. GRB/XRF 020427, detection of an underlying system with the VLT
  6. Gemini IR Detection of AXP 1E 2259+586 Post-Burst
  7. AXP 1E2259+586: quasi-simultaneous optical observation
  8. AXP 1E2259+586 optical observations
  9. GRB 020531, simultaneous optical observations
  10. GRB 020604, optical observations
  11. GRB 020531/Candidate Redshift
  12. GRB020531: Detection of Candidate Host Galaxy
  13. GRB 020418, optical/near-IR observations
  14. GRB020531: Upper Limit for Detection of Two TAROT Sources
  15. GRB 020603: Optical observations
  16. IPN detection of possible bursts from SGR1806-20
  17. HETE Observations of GX354-0 (= MXB1728-34, so-called "Slow
  18. XRF020427: Chandra Identification of a Likely X-ray Counterpart
  19. HST detection of the likely host galaxy of GRB 020124
  20. XRF020427: Chandra Observations and Candidate X-ray Counterparts
  21. GRB(XRF) 020427: X-ray afterglow with BeppoSAX
  22. GRB020321 : Optical observations.
  23. GRB020331: Third Epoch and Revised Second Epoch Optical
  24. The end of BSAX GRB activities
  25. GRB 020418: Optical observations
  26. GRB 020124: Optical observations
  27. GRB 020418: Optical observations
  28. GRB020410: BeppoSAX NFI observations refined analysis
  29. Mars Odyssey joins the IPN
  30. GRB020405: predicted break
  31. GRB 020409: Optical observations
  32. GRB 020409, No Optical Detection to R = 22
  33. GRB 020409: No Evidence for an Optical Afterglow
  34. GRB 020409, 2nd epoch optical observations
  35. GRB 020331 Kyoto observation on March 31
  36. GRB 020409
  37. GRB 020409, No Optical Detection to R = 20
  38. GRB020406(?), optical observations
  39. X-ray afterglow of GRB020321
  40. GRB020331: Confirmation of Afterglow Candidate with Magellan
  41. ASM GRB candidate 020406 refined error box
  42. GRB 020405: Moderate-resolution spectroscopy
  43. GRB020331: Optical Observations of Afterglow Candidate
  44. GRB020406(?), optical observations
  45. Revised Photometry of the Optical Afterglow of GRB 020405
  46. GRB 020331: Candidate Optical Afterglow
  47. GRB 020405: Decay index
  48. GRB020405, Radio Observations
  49. GRB020405: VLT spectroscopy
  50. Fading Optical Afterglow and Possible Host Galaxy of GRB 020405
  51. GRB 020405, U-band observations
  52. GRB 020405: Optical afterglow candidate
  53. GRB011212: Optical Observations
  54. GRB 020331: NIR Observations
  55. GRB 020331: NIR Observations
  56. GRB020331 NIR observation at KPNO (re-submission)
  57. GRB02033 NIR observation at KPNO
  58. GRB020331 field photometry
  59. GRB 020331, NIR observations
  60. GRB 020331: Optical observations
  61. GRB 020322: BeppoSAX observations of the X-ray afterglow
  62. GRB011211: HST Observations of Optical Afterglow and Host Galaxy
  63. GRB 020322, Radio observations
  64. Near-Infrared Observations of GRB020322 at TIRGO
  65. GRB 020321, Radio Observations
  66. GRB 020322: Optical Observations
  67. GRB020127: Proposed Host Galaxy Detection and Identification of Afterglow
  68. GRB 020321: Optical observations
  69. GRB020317 BVRI field photometry
  70. GRB 020322 optical observations
  71. GRB020322: Candidate Optical Afterglow
  72. GRB 020322 optical observation
  73. GRB020322, optical observations
  74. GRB 020322: Optical candidate
  75. GRB 020321: Optical observations
  76. GRB 011121: Fourth Epoch of HST Imaging
  77. GRB020321: BeppoSAX/NFI Observations
  78. GRB020321: a faint BeppoSAX detection
  79. GRB020305: NIR observations
  80. GRB020317 (=H1959): Localization by HETE of a Low Fluence GRB
  81. GRB 020305: Optical Observations
  82. GRB020317, optical observations
  83. GRB 020317: Optical observations
  84. GRB 011121: Third HST Epoch
  85. GRB020305: Properties of the Candidate Optical Afterglow
  86. GRB 011121: HST Observations reveal an intermediate-time multicolor
  87. GRB011121, possible supernova association
  88. GRB020305: Subaru Optical Observations
  89. GRB 020305: Optical observations
  90. XRF/GRB 011030: Detection of the Probable Host Galaxy
  91. GRB 020305: Candidate optical afterglow
  92. GRB020305 (=H1939): Localization of a GRB by HETE
  93. HST Imaging of the afterglow and host of GRB 011121
  94. GRB 010921: HST Observations
  95. IPN detection and localization of Cygnus X-1 flares
  96. GRB020127: Further VLA Observations of Possible Counterparts
  97. IPN detection of further SGR1900+14 activity
  98. IPN/HETE Detection of Bursts from SGR1900+14
  99. GRB020127: Palomar and VLA Observations of Possible Counterparts
  100. GRB020127: Comparison of Chandra Epochs and Identification of Possible Counterparts

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