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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"

6659 results found.

  1. Magellan Observations of GRB030725 (=H2779)
  2. XRF030723: Palomar observations and proposed counterpart
  3. XRF 030723, optical observations
  4. Konus-Wind detection of the bursts from SGR1806-20 region
  5. GRB030329: second XMM-Newton observation
  6. GRB030528(=H2724): X-ray Afterglow Identified in Second Epoch
  7. GRB 030528: Infrared Observations and the Proposed IR Counterpart
  8. GRB 030528: tentative NIR counterpart
  9. GRB 030416: Optical Observations
  10. GRB 030329: Optical limit (contemporaneous photography)
  11. GRB 030429: IR photometry with IRSF/SIRIUS
  12. GRB030501: TAROT candidate afterglow present in archival images
  13. GRB 030429: confirmation of afterglow candidate
  14. GRB 030329 Oprical observations in Rozhen observatory
  15. GRB030418: Kiso near infrared observations
  16. IPN triangulation of GRB030410 (annulus)
  17. GRB030329: Near Infrared Observations at Gunma
  18. GRB 030329 Optical observations
  19. GRB 030329, BVRI photometry
  20. GRB030329: Optical observations
  21. GRB030329, optical observation
  22. GRB030329, optical observation
  23. GRB 030329, BRI photometry
  24. GRB 030329: fading X-ray afterglow with RXTE
  25. GRB 030324: Optical and NIR Observations
  26. GRB030329: R and B observations
  27. GRB 030329: OT B and R photometry, decline rate
  28. GRB030329: Upper limits from recent and historical observations.
  29. GRB 030328: optical observations
  30. GRB 030328: OT photometry
  31. GRB030323: Detection on 2003/03/24
  32. GRB 030320: Optical Observations
  33. GRB 030324, optical observations
  34. GRB030226, addendum to GCN 1892
  35. GRB 030226 Optical observations
  36. GRB 030226: Ic Observations
  37. XMM-Newton observation of GRB030227
  38. GRB 030226: Confirmed decay index
  39. GRB030217: optical observations
  40. GRB 030204: Optical Observations
  41. GRB020819: Kiso R and I band observations
  42. GRB 030204, optical observations
  43. GRB030131: Kiso optical limit for corrected position
  44. GRB030131: Kiso Observations
  45. GRB 030115: Further IR observations with IRSF/SIRIUS
  46. GRB 030115: IR observations with IRSF/SIRIUS
  47. GRB 021219: OSN optical observations
  48. GRB021211: Kiso Observations
  49. GRB021204: Kiso Observations
  50. Chandra observation of the IPN error box of GRB021201 (short/hard)
  51. GRB021113: Kiso Observations
  52. Detection of activity from SGR 1900+14 with the RXTE/PCA
  53. GRB 021023: Curious K-band Source(s) Just Outside of IPN Localization
  54. GRB021004: High-resolution optical spectroscopy
  55. XRF 020903 spectrum
  56. GRB 021004 redshift
  57. HETE fluences for GRB021004
  58. GRB 021004: Optical Observations
  59. GRB021004: Optical Spectroscopy
  60. XRF 020903: Correction to GCN 1560
  61. XRF 020903: VRI observations
  62. GRB020812: optical observations
  63. GRB 020813 multiband optical observations
  64. GRB/XRF 020427, detection of an underlying system with the VLT
  65. SGR-like X-ray Bursts from AXP 1E 2259+586: follow-up
  66. SGR-like Bursts from the AXP 1E 2259+586
  67. GRB 020531/Candidate Redshift
  68. GRB 020418, optical/near-IR observations
  69. GRB 020603, R-band observation
  70. GRB020531, optical observations
  71. HST detection of the likely host galaxy of GRB 020124
  72. XRF020427: Chandra Observations and Candidate X-ray Counterparts
  73. GRB 020418: Optical observations
  74. GRB 020321: Candidate X-ray Counterparts
  75. GRB 020331: Candidate Optical Afterglow
  76. GRB 020331: NIR Observations
  77. GRB 020322: Optical Sources and Improved Astrometry
  78. GRB 020317: Optical observations
  79. GRB020127: Comparison of Chandra Epochs and Identification of Possible Counterparts
  80. GRB 020127, I-band observations starting 3.14-hr after the event
  81. VLT observations of GRB 020124: The fading optical/near-infrared afterglow
  82. GRB optical counterpart candidate in GCN 1217 is M dwarf
  83. GRB 011121: NIR observations, host galaxy?
  84. GRB 011121: Detection of Bright IR Counterpart
  85. Optical observation of SGR 1806-20 at the 6-m SAO telescope
  86. GRB001109, Host Galaxy Spectroscopic Observations
  87. SGR1806-20: Localization by HETE
  88. SGR 1900+14 : RXTE observations
  89. GRB 010222: Keck Spectroscopy
  90. GRB 010222, Decay Slope Confirmed
  91. Redshift of the Optical Transient of GRB010222
  92. GRB010220, Radio and Optical Observations
  93. GRB010214 Optical Observation
  94. GRB 001204: Ks observations
  95. GRB 001212 Optical Observation
  96. GRB 001212 possible OA in 2MASS
  97. GRB 001212 possible OA
  98. GRB 001105, further optical observations
  99. GRB001120, optical observations
  100. Optical/NIR observations of GRB001109

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