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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"

21585 results found.

  1. GRB 020331: Optical observations
  2. GRB 020321: Infrared observations
  3. GRB 020322: BeppoSAX observations of the X-ray afterglow
  4. GRB011211: HST Observations of Optical Afterglow and Host Galaxy
  5. GRB 020322, Radio observations
  6. Near-Infrared Observations of GRB020322 at TIRGO
  7. GRB 020321, Radio Observations
  8. GRB 020322: Optical Observations
  9. GRB 020321: Optical observations
  10. GRB020305 BVRI field photometry
  11. GRB 020322 optical observations
  12. GRB020317 : Near IR Observations from Mt Abu Observatory
  13. GRB020322, optical observations
  14. GRB020322: Optical Observations
  15. GRB020322: BeppoSAX/NFI Observations
  16. GRB 020321: Optical observations
  17. GRB020317: optical observations
  18. GRB020321 optical observations
  19. GRB020321: BeppoSAX/NFI Observations
  20. GRB020305: NIR observations
  21. GRB 020317 : KISO Optical Observations
  22. GRB 020305: Optical Observations
  23. GRB020317, optical observations
  24. GRB 020317: Optical observations
  25. GRB 011121: Third HST Epoch
  26. GRB 011121: HST Observations reveal an intermediate-time multicolor
  27. GRB011121, possible supernova association
  28. GRB011130 (XRF011130) Second Epoch Chandra Observations
  29. GRB020305: Subaru Optical Observations
  30. GRB 020305: Optical observations
  31. XRF/GRB 011030: Detection of the Probable Host Galaxy
  32. GRB 020305: Candidate optical afterglow
  33. Type Ic SN2002bl (SN/GRB?) Radio Observations
  34. GRB020305, optical observations
  35. GRB020305: Optical Observations
  36. GRB 020305: Optical observations
  37. HST Imaging of the afterglow and host of GRB 011121
  38. GRB 010921: HST Observations
  39. GRB020127: Further VLA Observations of Possible Counterparts
  40. RXTE Observations of SGR 1900+14
  41. GRB020127: Palomar and VLA Observations of Possible Counterparts
  42. GRB020127: Comparison of Chandra Epochs and Identification of Possible Counterparts
  43. SN2002ap (SN/GRB?) Echelle spectra
  44. SN2002ap (SN/GRB?) optical spectrographic observations
  45. GRB020127, WSRT radio observations
  46. GRB020127 Optical Observations
  47. SN 2002ap in M74
  48. SN2002ap (SN/GRB?) UBVRI Field Photometry
  49. GRB020127: Chandra Observations and Prospective Counterparts
  50. Type Ib/c SN2002ap (SN/GRB?)
  51. Type Ib/c SN2002ap (SN/GRB?) Radio Observations
  52. GRB020124, optical observations
  53. GRB020127: Optical observations
  54. GRB 020127, I-band observations starting 3.14-hr after the event
  55. GRB020127 Optical Observations -- Erratum to GCN 1230
  56. GRB010921 Optical Observations
  57. GRB020124: Optical observations
  58. VLT observations of GRB 020124: The fading optical/near-infrared afterglow
  59. GRB020124: Optical observations
  60. GRB 020124: Optical observations
  61. GRB 020124 Optical Observations
  62. IPN observations of SGR1806-20
  63. GRB 020124: Optical afterglow
  64. HETE 1896: Optical observations
  65. GRB optical counterpart candidate in GCN 1217 is M dwarf
  66. Possible optical counterpart to a GRB
  67. GRB011212, Optical Observations
  68. Optical polarization observations for GRB011211
  69. GRB 011130 and GRB 011212 - Milagro GeV/TeV Observations
  70. GRB011212: Optical observations at Gunma
  71. GRB 011130: Optical Observations of X-ray and Radio Sources
  72. GRB 011130, Radio/X-ray Comparison
  73. GRB011212: Optical observations
  74. GRB 011212: optical observation at Asiago
  75. GRB 011211: TNG Spectroscopic Observations
  76. GRB 011211, Optical Observations
  77. GRB011212: Optical observations
  78. GRB 011211 Optical Observations: Likely Afterglow
  79. GRB011130 (=XRF011130): Further analysis of Chandra Target of
  80. GRB 011130: Optical Observations of Chandra Sources
  81. GRB 011130: Optical Observations of Chandra sources
  82. GRB011130 (XRF011130) Chandra Observations
  83. Sub-mm and Centimeter Detections of the Host Galaxy of GRB000418
  84. GRB011130, optical observations
  85. GRB 011130, K band observations
  86. GRB011130, optical observations
  87. GRB 011130 I-band Observation
  88. GRB011130 (XRF011130) optical observations
  89. GRB011130 (XRF011130) SDSS PT i-band observations
  90. XRF011130: Infrared Observations
  91. GRB011130, Radio Observations
  92. GRB011130 (=XRF011130), Optical Observations
  93. XRF011130: NEAT Optical Observations
  94. GRB 011121
  95. GRB 011121: J-band observations
  96. GRB 011121: NIR observations, host galaxy?
  97. GRB010921 - Milagro GeV/TeV Observations
  98. GRB 011121: HST Scheduled
  99. GRB011121: fainter still
  100. GRB011121: UBRI Observations

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