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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"

24892 results found.

  1. GRB030131, BVRcIc field photometry
  2. Possible GRB030323 localized by INTEGRAL
  3. GRB030323: Detection on 2003/03/24
  4. IPN triangulation of GRB030326 (single small error box)
  5. IPN triangulation of GRB030325 (two small error boxes)
  6. GRB030323: V, R, I photometry
  7. GRB030323 (=H2640): A Faint, Long GRB Localized by the HETE WXM and SXC
  8. GRB030324 (=H2641): A Long GRB Localized in Real Time by the HETE WXM
  9. VLT/FORS2 spectra of GRB 030323
  10. GRB030323, optical observations
  11. GRB030324, BVRcIc field photometry
  12. GRB030323, BVRcIc field calibration
  13. IPN triangulation of GRB030320 (small error box)
  14. Possible GRB 030320 localized by INTEGRAL
  15. IPN triangulation of GRB030306 (single small error box - REVISED)
  16. IPN triangulation of GRB030306 (single small error box)
  17. IPN triangulation of GRB030306 (two small error boxes)
  18. GRB030226, BVRc observations
  19. Chandra detection of the X-ray afterglow of GRB 030226
  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 - faint tentative OT candidate
  29. GRB 030226, optical observations
  30. XMM-Newton observation of GRB030227
  31. GRB030227: Kiso optical observations
  32. GRB 030227: Kyoto optical observation
  33. GRB 030226, optical light curve
  34. GRB030227 localized by INTEGRAL
  35. GRB 030226 : Predicted light curve
  36. GRB030226: ESI spectroscopy
  37. GRB030226 (=U10893): A Long GRB Localized by the HETE WXM and SXC
  38. GRB 030226 simultaneous optical observations
  39. GRB 030226, optical observations
  40. GRB030226: Optical decay index
  41. GRB 030226 Optical Spectra and R,I,z' Imaging
  42. GRB: Non-Referencing of GCN Circulars.
  43. IPN triangulation of GRB030217 (small error box)
  44. GRB 030131: marginal optical detection
  45. GRB 030204: Optical Observations
  46. GRB030204 field photometry
  47. GRB020819: Kiso R and I band observations
  48. GRB030131: Candidate Optical Afterglow
  49. IPN triangulation of GRB030204 (small error box)
  50. GRB 030131, optical observations
  51. GRB 030131: afterglow candidate
  52. GRB 030115, late-time optical observations
  53. GRB030131: corrected INTEGRAL position
  54. GRB 020819: Host galaxy at Radio Position
  55. IPN triangulation of GRB030131
  56. GRB 030131 optical observations
  57. GRB 030131 optical observations
  58. A long GRB detected by INTEGRAL
  59. GRB030115: 1.2 mm upper limits with MAMBO @ IRAM 30m
  60. GRB 030115, simultaneous observations by BOOTES-1
  61. GRB 030115: IR observations with IRSF/SIRIUS
  62. IPN triangulation of GRB030115C (large error box)
  63. GRB030115, afterglow candidate
  64. GRB 021211: R-band observations at late-time
  65. GRB030115: Optical Observations, Swiss Telescope at La Silla (ESO, Chile)
  66. GRB 030115 : Possible IR counterpart
  67. GRB030115 (=H2533): A Long GRB Localized by the HETE WXM and SXC
  68. Distribution of INTEGRAL SPI-ACS triggers for GRB bursts
  69. GRB 030115: APO Optical Observations
  70. Information about where HETE will be pointing
  71. VLT spectroscopy of the probable host of GRB 021211
  72. IPN triangulation of GRB030101 (two large error boxes)
  73. GRB 021211: Probable Host and Underlying Supernova
  74. GRB 021112: Evidence for Another Dark Optical Afterglow
  75. GRB 021219: OSN optical observations
  76. GRB021219, optical observations
  77. GRB021219, optical observation by MASTER
  78. VLT spectra of GRB 021211 revisited
  79. GRB021219: a long GRB localized by INTEGRAL
  80. GRB021211: APO optical observations
  81. XRF 020903 : HST observations
  82. GRB 021201: Optical Observations
  83. GRB 021211: CTIO observations
  84. GRB021211, BVRI field photometry
  85. GRB021211: Optical observations in CrAO
  86. GRB 021211, optical observations
  87. GRB021211: Kiso Observations
  88. GRB 021201, optical observations
  89. GRB021211: Optical observations
  90. GRB 021201 (short/hard), NOT observations
  91. SUB-MM SEARCH FOR GRB 021211
  92. Chandra observation of the IPN error box of GRB021201 (short/hard)
  93. GRB 021211, R- and I-band observations
  94. GRB021211 - Upper limits from recent and historical observations
  95. GRB021211 (=H2493): A Bright, Long GRB Localized by HETE-2 in Near-Real Time
  96. IPN triangulation of GRB021206 (small error box)
  97. IPN triangulation of GRB021205 (large error box)
  98. GRB021201, BVRcIc field photometry
  99. GRB 021201: BOOTES simultaneous optical observations
  100. IPN triangulation of GRB021201 (short/hard burst, small error box)

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