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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"

21264 results found.

  1. GRB030328 (=H2650): A Long, Bright GRB Localized by the HETE WXM and SXC
  2. GRB 030328: Optical observations
  3. GRB030324 optical observation
  4. GRB030131, BVRcIc field photometry
  5. Possible GRB030323 localized by INTEGRAL
  6. GRB030323: Detection on 2003/03/24
  7. GRB030324, optical observations
  8. GRB030323: V, R, I photometry
  9. GRB030323 (=H2640): A Faint, Long GRB Localized by the HETE WXM and SXC
  10. GRB030324 (=H2641): A Long GRB Localized in Real Time by the HETE WXM
  11. VLT/FORS2 spectra of GRB 030323
  12. GRB030323, ROTSE-III detection of possible optical counterpart
  13. GRB030323, optical observations
  14. GRB030324, BVRcIc field photometry
  15. GRB030323, BVRcIc field calibration
  16. Possible GRB 030320 localized by INTEGRAL
  17. GRB030226, BVRc observations
  18. Chandra detection of the X-ray afterglow of GRB 030226
  19. GRB 030226: Ic Observations
  20. GRB030227: Kiso optical upper limit
  21. GRB030227, BVRcIc field photometry
  22. GRB030226, BVRcIc field calibration
  23. GRB 030228, optical observations
  24. GRB 030227: Confirmed Optical Afterglow (S1-A)
  25. GRB 030227: fading of candidate optical afterglow 'S1-A'
  26. GRB030227:Optical observations
  27. GRB 030227, possible optical counterpart of XMM-Newton source
  28. GRB030227: Kiso optical observations
  29. GRB 030227: Kyoto optical observation
  30. GRB030227 localized by INTEGRAL
  31. Possible break in the GRB 030226 light curve
  32. GRB030226: ESI spectroscopy
  33. GRB030226 (=U10893): A Long GRB Localized by the HETE WXM and SXC
  34. GRB 030226 simultaneous optical observations
  35. GRB 030226, optical observations
  36. GRB030226: Optical decay index
  37. GRB 030217: Optical Observations at 4, 5, and 6 Days
  38. GRB 030131: marginal optical detection
  39. GRB 030204: Optical Observations
  40. GRB030204 field photometry
  41. GRB020819: Kiso R and I band observations
  42. GRB030131: Candidate Optical Afterglow
  43. GRB 030131, optical observations
  44. GRB 030131: afterglow candidate
  45. GRB 030115, late-time optical observations
  46. GRB030131: corrected INTEGRAL position
  47. GRB 020819: Host galaxy at Radio Position
  48. IPN triangulation of GRB030131
  49. GRB 030131 optical observations
  50. GRB030131: refined position
  51. GRB 030131 optical observations
  52. A long GRB detected by INTEGRAL
  53. GRB030115: 1.2 mm upper limits with MAMBO @ IRAM 30m
  54. GRB 030115, simultaneous observations by BOOTES-1
  55. GRB 030115: IR observations with IRSF/SIRIUS
  56. GRB030115, afterglow candidate
  57. GRB030115: Optical Observations, Swiss Telescope at La Silla (ESO, Chile)
  58. GRB 030115 : Possible IR counterpart
  59. Distribution of INTEGRAL SPI-ACS triggers for GRB bursts
  60. GRB 030115: APO Optical Observations
  61. IPN triangulation of GRB030102 (annulus)
  62. VLT spectroscopy of the probable host of GRB 021211
  63. GRB 021211: Probable Host and Underlying Supernova
  64. GRB 021112: Evidence for Another Dark Optical Afterglow
  65. GRB 021219: OSN optical observations
  66. GRB021219, optical observations
  67. GRB021219, optical observation by MASTER
  68. GRB021219: a long GRB localized by INTEGRAL
  69. GRB021211: APO optical observations
  70. IPN detection of continued activity from SGR1806-20
  71. XRF 020903 : HST observations
  72. GRB 021201: Optical Observations
  73. GRB 021211: CTIO observations
  74. GRB 021211: early break in light curve
  75. GRB021211, BVRI field photometry
  76. GRB021211: Optical observations in CrAO
  77. GRB 021211, optical observations
  78. GRB021211: Kiso Observations
  79. GRB 021201, optical observations
  80. GRB021211: Optical observations
  81. GRB 021201 (short/hard), NOT observations
  82. Chandra observation of the IPN error box of GRB021201 (short/hard)
  83. GRB 021211, R- and I-band observations
  84. GRB021211 - Upper limits from recent and historical observations
  85. GRB 021204: I-band Observations
  86. GRB021211 (=H2493): A Bright, Long GRB Localized by HETE-2 in Near-Real Time
  87. GRB 021125: Radio Observations
  88. IPN detection of renewed activity from SGR1806-20
  89. GRB 021104, GRB 021112 and GRB 021113 - Milagro GeV/TeV Observations
  90. GRB021201, BVRcIc field photometry
  91. GRB 021201: BOOTES simultaneous optical observations
  92. GRB021004, late time optical observations
  93. GRB021125 : A long GRB localized by INTEGRAL
  94. GRB 021112: Afterglow or Variable Star?
  95. GRB021113: optical observations at Bisei
  96. GRB 021113: Evidence for a Dark Optical Afterglow
  97. GRB021112, BVRI field photometry
  98. GRB 021112: Variable Source in R-band search
  99. GRB021112: Optical Observations
  100. GRB 021113: Optical observations

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