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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"

21801 results found.

  1. GRB030115: R-band observations at Asiago
  2. GRB030115: TAROT optical observations
  3. GRB 021211: VLT spectrum
  4. GRB 030115: APO Optical Observations
  5. GRB 030115, no optical candidate
  6. GRB 030115, optical observations
  7. GRB 030115, optical candidate
  8. Information about where HETE will be pointing
  9. VLT spectroscopy of the probable host of GRB 021211
  10. GRB 021211: Probable Host and Underlying Supernova
  11. GRB021211, radio observations
  12. GRB 021219: OSN optical observations
  13. GRB021219: Radio Observations
  14. GRB021219, optical observations
  15. IPN triangulation of GRB021219
  16. VLT spectra of GRB 021211 revisited
  17. GRB021211: APO optical observations
  18. XRF 020903 : HST observations
  19. GRB 021201: Optical Observations
  20. GRB 021211, optical observations
  21. GRB 021211: CTIO observations
  22. VLT spectrum of GRB 021211
  23. GRB 021211: early break in light curve
  24. GRB021211: Optical observations in CrAO
  25. GRB 021211, IR observations
  26. GRB 021211, optical observations
  27. GRB 021211: Optical Observations
  28. GRB021211: Kiso Observations
  29. GRB021204: Kiso Observations
  30. GRB 021201, optical observations
  31. GRB 021211: Radio Observations
  32. GRB021211: Optical observations
  33. GRB 021201 (short/hard), NOT observations
  34. SUB-MM SEARCH FOR GRB 021211
  35. GRB 021211 Milagro GeV/TeV Observations
  36. GRB 021211, R- and I-band observations
  37. GRB021211 - Upper limits from recent and historical observations
  38. GRB021211, OT at 108 s
  39. GRB 021204: I-band Observations
  40. HETE 2493: Optical observations
  41. HETE 2493: Optical observations
  42. HETE 2493: Optical candidate
  43. GRB 021204: Optical Observations at RIKEN
  44. GRB 021125: Radio Observations
  45. GRB 021104, GRB 021112 and GRB 021113 - Milagro GeV/TeV Observations
  46. GRB 021201, Radio Observations
  47. GRB 021201: Optical Observations
  48. GRB 021201: BOOTES simultaneous optical observations
  49. GRB021004, late time optical observations
  50. GRB 021112: Afterglow or Variable Star?
  51. GRB021113: optical observations at Bisei
  52. GRB 021113: Evidence for a Dark Optical Afterglow
  53. GRB 021112, Radio Observations
  54. GRB 021112: Variable Source in R-band search
  55. GRB021112: Optical Observations
  56. GRB021113: Kiso Observations
  57. GRB 021113: Optical observations
  58. GRB 021112: RAPTOR Observations
  59. GRB 021113: Optical Observations
  60. GRB 021113: Optical Observations
  61. GRB 021112: Optical Observations
  62. GRB 021112: R-band search
  63. GRB 021016: Optical Observations
  64. GRB021004: Near infrared spectroscopy
  65. GRB021104: Optical Observations
  66. GRB021104: Optical observations
  67. GRB021104: optical observations
  68. Detection of activity from SGR 1900+14 with the RXTE/PCA
  69. GRB021004, late-time optical observations
  70. GRB 021004: optical observations
  71. GRB021004: Optical Observations
  72. GRB 020813; likely host galaxy.
  73. GRB 021008, radio observations
  74. GRB 021016, optical observations
  75. GRB 021004: VRI observations at TNG: possible break
  76. GRB021016, optical observations
  77. GRB 021008, optical observations
  78. GRB021004: Optical Observations
  79. GRB 021004: optical spectroscopy on Oct 11
  80. GRB021004: High-resolution optical spectroscopy
  81. XRF 020903: flattening of the optical light curve.
  82. GRB021004: Optical Observations
  83. GRB 021004 submm observations
  84. GRB021004 Chandra HETG Observations
  85. GRB 021004: Optical/NIR Observations
  86. GRB 021004: Additional V-band Polarimetric Observations
  87. GRB 021004: Host Galaxy Star Formation Rate
  88. GRB 021004 submm observations
  89. GRB 021004: WC wind?
  90. GRB021004: NIR and Optical observations
  91. GRB 021004: Optical observations, AUDE network
  92. GRB 021004 - VLA Radio Observations
  93. GRB 021004 - Unusual Radio-to-Submm Spectrum
  94. GRB 021004: optical spectroscopy
  95. XRF 020903 spectrum
  96. GRB 021004: HST/STIS spectroscopic observations
  97. GRB021004: optical observations and predicted break time
  98. GRB021004: BVRc photometry
  99. GRB 021004 redshift
  100. GRB 021004 continued IR fading

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