Ionized Nitrogen at High Redshift

TY - JOUR

T1 - Ionized Nitrogen at High Redshift

AU - Decarli, R.

AU - Walter, F.

AU - Neri, R.

AU - Cox, P.

AU - Bertoldi, F.

AU - Kneib, J.P.

AU - Lestrade, J.F.

AU - Maiolino, R.

AU - Omont, A.

AU - Richard, Johan

AU - Riechers, D.

AU - Thanjavur, K.

AU - Weiss, A.

PY - 2012/6/10

Y1 - 2012/6/10

N2 - We present secure [N II]205 μm detections in two millimeter-bright, strongly lensed objects at high redshift, APM08279+5255 (z = 3.911) and MM18423+5938 (z = 3.930), using the IRAM Plateau de Bure Interferometer. Due to its ionization energy [N II]205 μm is a good tracer of the ionized gas phase in the interstellar medium. The measured fluxes are S([N II]205 μm) = (4.8 ± 0.8)Jykms-1 and (7.4 ± 0.5)Jykms-1, respectively, yielding line luminosities of L([N II]205 μm) = (1.8 ± 0.3) × 109 μ-1 L for APM08279+5255 and L([N II]205 μm) = (2.8 ± 0.2) × 109 μ-1 L for MM18423+5938. Our high-resolution map of the [N II]205 μm and 1mm continuum emission in MM18423+5938 clearly resolves an Einstein ring in this source and reveals a velocity gradient in the dynamics of the ionized gas. A comparison of these maps with high-resolution EVLA CO observations enables us to perform the first spatially resolved study of the dust continuum-to-molecular gas surface brightness (Σ FIRΣN CO, which can be interpreted as the star formation law) in a high-redshift object. We find a steep relation (N = 1.4 ± 0.2), consistent with a starbursting environment. We measure a [N II]205 μm/FIR luminosity ratio in APM08279+5255 and MM18423+5938 of 9.0 × 10-6 and 5.8 × 10-6, respectively. This is in agreement with the decrease of the [N II]205 μm/FIR ratio at high FIR luminosities observed in local galaxies.

AB - We present secure [N II]205 μm detections in two millimeter-bright, strongly lensed objects at high redshift, APM08279+5255 (z = 3.911) and MM18423+5938 (z = 3.930), using the IRAM Plateau de Bure Interferometer. Due to its ionization energy [N II]205 μm is a good tracer of the ionized gas phase in the interstellar medium. The measured fluxes are S([N II]205 μm) = (4.8 ± 0.8)Jykms-1 and (7.4 ± 0.5)Jykms-1, respectively, yielding line luminosities of L([N II]205 μm) = (1.8 ± 0.3) × 109 μ-1 L for APM08279+5255 and L([N II]205 μm) = (2.8 ± 0.2) × 109 μ-1 L for MM18423+5938. Our high-resolution map of the [N II]205 μm and 1mm continuum emission in MM18423+5938 clearly resolves an Einstein ring in this source and reveals a velocity gradient in the dynamics of the ionized gas. A comparison of these maps with high-resolution EVLA CO observations enables us to perform the first spatially resolved study of the dust continuum-to-molecular gas surface brightness (Σ FIRΣN CO, which can be interpreted as the star formation law) in a high-redshift object. We find a steep relation (N = 1.4 ± 0.2), consistent with a starbursting environment. We measure a [N II]205 μm/FIR luminosity ratio in APM08279+5255 and MM18423+5938 of 9.0 × 10-6 and 5.8 × 10-6, respectively. This is in agreement with the decrease of the [N II]205 μm/FIR ratio at high FIR luminosities observed in local galaxies.

U2 - 10.1088/0004-637X/752/1/2

DO - 10.1088/0004-637X/752/1/2

M3 - Journal article

SN - 0004-637X

VL - 752

SP - 2

JO - Astrophysical Journal

JF - Astrophysical Journal

IS - 1

ER -