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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"

45421 results found.

  1. GRB 990510 Optical Observations
  2. GRB 990510, BVI photometry
  3. GRB 990510 optical observations
  4. GRB 990510: BeppoSAX/GRBM observations
  5. GRB990510 optical observations
  6. GRB990510
  7. GRB 990510 optical observations
  8. GRB 990510 optical observations
  9. Galactic extinction towards GRB 990510
  10. GRB990510: NFI X-ray source
  11. GRB 990510 optical observations
  12. IPN localization of GRB990510
  13. GRB 990506 Radio Observations
  14. GRB 990123, optical monitoring
  15. GRB 990506: BATSE Observations
  16. GRB 990506, optical observations
  17. GRB 990510: Final BeppoSAX-WFC Coordinates
  18. GRB 990506, Optical Observations
  19. GRB 990506 optical observations
  20. GRB 990506 optical observations
  21. GRB 990506, optical observations
  22. GRB990506 observation plan
  23. Refined IPN error box for GRB990506
  24. GRB 990506: Limits on the possible optical transient
  25. GRB 990506, armchair astronomy
  26. GRB 990506, optical observations from +1 to +3 hours
  27. GRB 990506, optical observations
  28. GRB990506 Optical observations
  29. New IPN/RXTE error box for GRB990506
  30. IPN localization for GRB990506
  31. GRB 970228: Redshift and properties of the host galaxy
  32. IPN localization of GRB990427
  33. GRB981220 VLBA observations
  34. GRB980425 Optical observations of exponential decline at late time
  35. GRB990321 REFINED IPN ANNULUS
  36. GRB990323 PRECISE IPN POSITION
  37. GRB990321 IPN TRIANGULATION
  38. GRB 990316 Optical Observations
  39. GRB 990316, Radio observations
  40. GRB 990316, Optical observations
  41. GRB990316, Optical observations
  42. GRB 990316 optical observations
  43. GRB990316: simultaneous optical observation
  44. GRB990316 - Optical null results
  45. ASM/IPN error box for GRB 990308 (BATSE #7457)
  46. GRB990308 not a new SGR
  47. GRB 990308a and GRB 990308b
  48. GRB990308 (Trig. 7457), optical observations
  49. GRB990308, Possible new SGR~0209+70
  50. GRB981220, IPN localization
  51. GRB 981220, radio observations
  52. GRB 990123, Field Photometry
  53. GRB 990217 Optical Observations
  54. GRB 990217, radio observations
  55. BATSE Resumes Normal Operations
  56. GRB990217: BeppoSAX/GRBM data
  57. Optical Observations of GRB990217
  58. GRB990123: Caltech STIS Photometry and Images
  59. GRB990123 observations
  60. GRB990217, WFC position
  61. GRB990123, Optical Observation
  62. GRB 990123: Discovery of the Probable Host Galaxy
  63. GRB 990123: Reduced HST Images
  64. For Immediate Posting to GCN - HST Data GRB 990123 Available
  65. GRB19990123 observations
  66. GRB 990123: BVRI standards in the field
  67. GRB 990123: Updated Keck Spectroscopy Results
  68. GRB981220, field photometry
  69. GRB 990123 NOT Spectrum Update
  70. GRB990123, Optical observation
  71. GRB990123, is the "radio flare" due to an inhomogeneous medium?
  72. GRB 990123: Publicly available reduced HST images
  73. GRB990123, Upcoming HST Service Observations
  74. GRB990123, 15-GHz limits
  75. GRB 990123: New Constraints on Possible Foreground Galaxies
  76. GRB990123 Optical Observations
  77. GRB990123, Probability of gravitational lensing
  78. GRB 990123: Detection of the IR Transient, and the Light Curve Fits
  79. GRB 990123: Continued Radio Observations
  80. GRB990123, Preliminary Lens Search Results
  81. GRB 990123: Correction to GCN 230 - C.A. Young added to author list
  82. On the Lensing Interpretation of GRB 990123
  83. Search for Potential Images of GRB 990123
  84. Search for Potential Images of GRB 990123
  85. GRB990123, Optical BVRI Observations
  86. GRB 990123: near-infrared observations.
  87. GRB990123, OSSE observations
  88. GRB990123: NIR Observation
  89. GRB990123, ASCA X-ray observation of afterglow
  90. "GRB 990123: New BV Observations"
  91. GRB 990123 Optical Follow-Up
  92. GRB 990123; Addendum to GCN 223
  93. GRB 990123: BATSE Observations
  94. GRB 990123 Keck Spectrum update
  95. GRB990123 IPN annulus
  96. GRB 990123 : Multiple and Distorted Images of the Host Galaxy?
  97. GRB990123 Optical Observations
  98. GRB 990123 Spectroscopic Redshifts
  99. GRB 990123: New Optical Observations, Decay Measure
  100. GRB 990123 Optical Follow-Up

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Download all Circulars as a .tar.gz archive (updated once a day):
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