Abstract
We present Ha and [OIII] (5007 Å) images of the nebula powered by the jet of the black hole candidate and microquasar Cygnus X-1, observed with the 2.5-m Isaac Newton Telescope (INT). The ring-like structure is luminous in [OIII] and there exists a thin outer shell with a high [OIII]/Hα flux ratio. This outer shell probably originates in the collisionally excited atoms close to the front of the bow shock. Its presence indicates that the gas is shock excited as opposed to photoionized, supporting the jet-powered scenario. The shock velocity was previously constrained at 20 < vs < 360 km s-1; here we show that vs ≥ 100 km s-1 (lσ confidence) based on a comparison of the observed [OIII]/Hα ratio in the bow shock with a number of radiative shock models. From this we further constrain the time-averaged power of the jet: PJet = (4-14) × 1036 erg s-1. The Ha flux behind the shock front is typically 4 × 10-15 erg s-1 cm-2 arcsec-2, and we estimate an upper limit of ∼ 8 × 10 -15 erg s-1 cm-2 arcsec-2 (3σ) to the optical (R-band) continuum flux of the nebula. The inferred age of the structure is similar to the time Cyg X-1 has been close to a bright H II region (due to the proper motion of the binary), indicating a dense local medium is required to form the shock wave. In addition, we search a > 1 deg2 field of view to the south of Cyg X-1 in Hα (provided by the INT Photometric Ha Survey of the Northern Galactic Plane; IPHAS) for evidence of the counter jet interacting with the surrounding medium. Two candidate regions are identified, whose possible association with the jet could be confirmed with follow-up observations in [S II] and deeper observations in [OIII] and radio.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 1341-1349 |
| Number of pages | 9 |
| Journal | Monthly Notices of the Royal Astronomical Society |
| Volume | 376 |
| Issue number | 3 |
| DOIs | |
| State | Published - Apr 1 2007 |
Fingerprint
Keywords
- Accretion, accretion discs
- Black hole physics
- ISM: jets and outflows
- Shock waves
- Stars: individual: Cygnus X-1
- X-rays: binaries
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science
Cite this
The jet-powered optical nebula of Cygnus X-1. / Russell, Dave; Fender, R. P.; Gallo, E.; Kaiser, C. R.
In: Monthly Notices of the Royal Astronomical Society, Vol. 376, No. 3, 01.04.2007, p. 1341-1349.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - The jet-powered optical nebula of Cygnus X-1
AU - Russell, Dave
AU - Fender, R. P.
AU - Gallo, E.
AU - Kaiser, C. R.
PY - 2007/4/1
Y1 - 2007/4/1
N2 - We present Ha and [OIII] (5007 Å) images of the nebula powered by the jet of the black hole candidate and microquasar Cygnus X-1, observed with the 2.5-m Isaac Newton Telescope (INT). The ring-like structure is luminous in [OIII] and there exists a thin outer shell with a high [OIII]/Hα flux ratio. This outer shell probably originates in the collisionally excited atoms close to the front of the bow shock. Its presence indicates that the gas is shock excited as opposed to photoionized, supporting the jet-powered scenario. The shock velocity was previously constrained at 20 < vs < 360 km s-1; here we show that vs ≥ 100 km s-1 (lσ confidence) based on a comparison of the observed [OIII]/Hα ratio in the bow shock with a number of radiative shock models. From this we further constrain the time-averaged power of the jet: PJet = (4-14) × 1036 erg s-1. The Ha flux behind the shock front is typically 4 × 10-15 erg s-1 cm-2 arcsec-2, and we estimate an upper limit of ∼ 8 × 10 -15 erg s-1 cm-2 arcsec-2 (3σ) to the optical (R-band) continuum flux of the nebula. The inferred age of the structure is similar to the time Cyg X-1 has been close to a bright H II region (due to the proper motion of the binary), indicating a dense local medium is required to form the shock wave. In addition, we search a > 1 deg2 field of view to the south of Cyg X-1 in Hα (provided by the INT Photometric Ha Survey of the Northern Galactic Plane; IPHAS) for evidence of the counter jet interacting with the surrounding medium. Two candidate regions are identified, whose possible association with the jet could be confirmed with follow-up observations in [S II] and deeper observations in [OIII] and radio.
AB - We present Ha and [OIII] (5007 Å) images of the nebula powered by the jet of the black hole candidate and microquasar Cygnus X-1, observed with the 2.5-m Isaac Newton Telescope (INT). The ring-like structure is luminous in [OIII] and there exists a thin outer shell with a high [OIII]/Hα flux ratio. This outer shell probably originates in the collisionally excited atoms close to the front of the bow shock. Its presence indicates that the gas is shock excited as opposed to photoionized, supporting the jet-powered scenario. The shock velocity was previously constrained at 20 < vs < 360 km s-1; here we show that vs ≥ 100 km s-1 (lσ confidence) based on a comparison of the observed [OIII]/Hα ratio in the bow shock with a number of radiative shock models. From this we further constrain the time-averaged power of the jet: PJet = (4-14) × 1036 erg s-1. The Ha flux behind the shock front is typically 4 × 10-15 erg s-1 cm-2 arcsec-2, and we estimate an upper limit of ∼ 8 × 10 -15 erg s-1 cm-2 arcsec-2 (3σ) to the optical (R-band) continuum flux of the nebula. The inferred age of the structure is similar to the time Cyg X-1 has been close to a bright H II region (due to the proper motion of the binary), indicating a dense local medium is required to form the shock wave. In addition, we search a > 1 deg2 field of view to the south of Cyg X-1 in Hα (provided by the INT Photometric Ha Survey of the Northern Galactic Plane; IPHAS) for evidence of the counter jet interacting with the surrounding medium. Two candidate regions are identified, whose possible association with the jet could be confirmed with follow-up observations in [S II] and deeper observations in [OIII] and radio.
KW - Accretion, accretion discs
KW - Black hole physics
KW - ISM: jets and outflows
KW - Shock waves
KW - Stars: individual: Cygnus X-1
KW - X-rays: binaries
UR - http://www.scopus.com/inward/record.url?scp=34147102888&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=34147102888&partnerID=8YFLogxK
U2 - 10.1111/j.1365-2966.2007.11539.x
DO - 10.1111/j.1365-2966.2007.11539.x
M3 - Article
AN - SCOPUS:34147102888
VL - 376
SP - 1341
EP - 1349
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
SN - 0035-8711
IS - 3
ER -