The HIFI spectral survey of AFGL 2591 (CHESS)

Kaźmierczak-Barthel, Maja; Tak, F. F. S. van der; Helmich, Frank; Chavarría, L.; Wang, K.-S.; Ceccarelli, C.

doi:10.1051/0004-6361/201322819

Cited by 14 publications

(19 citation statements)

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“…Water emission attributed to the outflow component is observed with HIFI in multiple transitions as a broad feature (van der Tak et al 2013;Kaźmierczak-Barthel et al 2014;Choi et al 2015), but is centered closer to the systemic velocity of the envelope than the absorption we see. Analysis of the H 2 O outflow emission by Choi et al (2015) .…”

Section: Discussionmentioning

confidence: 51%

“…The pure rotational 1 1,1 -0 0,0 transition of H 2 O at 1113.343 GHz (269.3 μm) is seen in both emission and absorption toward AFGL 2591 (van der Tak et al 2013;Kaźmierczak-Barthel et al 2014;Choi et al 2015). The emission component arises in the protostellar envelope, and the absorption components in the blueshifted outflow and foreground gas.…”

Section: Discussionmentioning

confidence: 97%

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Sofia/Exes Observations of Water Absorption in the Protostar Afgl 2591 at High Spectral Resolution

Indriolo

Neufeld

DeWitt

et al. 2015

ApJ

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We present high spectral resolution (∼3 km s −1 ) observations of the n 2 ro-vibrational band of H 2 O in the 6.086-6.135 μm range toward the massive protostar AFGL 2591 using the Echelon-Cross-Echelle Spectrograph (EXES) on the Stratospheric Observatory for Infrared Astronomy (SOFIA). Ten absorption features are detected in total, with seven caused by transitions in the n 2 band of H 2 O, two by transitions in the first vibrationally excited n 2 band of H 2 O, and one by a transition in the n 2 band of H 2 18 O. Among the detected transitions is the n 2 1 1,1 -0 0,0 line that probes the lowest-lying rotational level of para-H 2 O. The stronger transitions appear to be optically thick, but reach maximum absorption at a depth of about 25%, suggesting that the background source is only partially covered by the absorbing gas or that the absorption arises within the 6 μm emitting photosphere. Assuming a covering fraction of 25%, the H 2 O column density and rotational temperature that best fit the observed absorption

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Section: Discussionmentioning

confidence: 51%

Section: Discussionmentioning

confidence: 97%

Sofia/Exes Observations of Water Absorption in the Protostar Afgl 2591 at High Spectral Resolution

Indriolo

Neufeld

DeWitt

et al. 2015

ApJ

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“…The J = 10-9 transition was observed as part of the WISH key programme for the entire low-and intermediate-mass sample and for the high-mass object W3-IRS5 (see San José-García et al 2013). The J = 10-9 spectrum was obtained for AFGL 2591 from the work of Kaźmierczak-Barthel et al (2014). For the other high-mass sources, 12 CO J = 3-2 spectra are used as a proxy (San José-García et al 2013).…”

Section: Additional 12 Co Observationsmentioning

confidence: 99%

Linking low- to high-mass young stellar objects withHerschel-HIFI observations of water

José-García

Mottram

Dishoeck

et al. 2015

A&A

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Context. Water probes the dynamics in young stellar objects (YSOs) effectively, especially shocks in molecular outflows. It is therefore a key molecule for exploring whether the physical properties of low-mass protostars can be extrapolated to massive YSOs, an important step in understanding the fundamental mechanisms regulating star formation. Aims. As part of the WISH key programme, we investigate excited water line properties as a function of source luminosity, in particular the dynamics and the excitation conditions of shocks along the outflow cavity wall. Methods. Velocity-resolved Herschel-HIFI spectra of the H 2 O 2 02 -1 11 (988 GHz), 2 11 -2 02 (752 GHz) and 3 12 -3 03 (1097 GHz) lines were analysed, together with 12 CO J = 10-9 and 16-15, for 52 YSOs with bolometric luminosities ranging from <1 to >10 5 L . The H 2 O and 12 CO line profiles were decomposed into multiple Gaussian components which are related to the different physical structures of the protostellar system. The non-LTE radiative transfer code radex was used to constrain the excitation conditions of the shocks along the outflow cavity.Results. The profiles of the three excited water lines are similar, indicating that they probe the same gas. Two main emission components are seen in all YSOs: a broad component associated with non-dissociative shocks in the outflow cavity wall ("cavity shocks") and a narrow component associated with the quiescent envelope material. More than 60% of the total integrated intensity in the excited water lines comes from the broad cavity shock component, while the remaining emission comes mostly from the envelope for low-mass Class I, intermediate-and high-mass objects, and dissociative "spot shocks" for low-mass Class 0 protostars. The widths of the water lines are surprisingly similar from low-to high-mass YSOs, whereas 12 CO J = 10-9 line widths increase slightly with L bol . The excitation analysis of the cavity shock component shows stronger 752 GHz emission for high-mass YSOs, most likely due to pumping by an infrared radiation field. Finally, a strong correlation with slope unity is measured between the logarithms of the total H 2 O line luminosity, L H 2 O , and L bol , which can be extrapolated to extragalactic sources. This linear correlation, also found for CO, implies that both species primarily trace dense gas directly related to star formation activity. Conclusions. The water emission probed by spectrally unresolved data is largely due to shocks. Broad water and high-J CO lines originate in shocks in the outflow cavity walls for both low-and high-mass YSOs, whereas lower-J CO transitions mostly trace entrained outflow gas. The higher UV field and turbulent motions in high-mass objects compared to their low-mass counterparts may explain the slightly different kinematical properties of 12 CO J = 10-9 and H 2 O lines from low-to high-mass YSOs.

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“…The IR lines are shown as optical depth profiles. The sub-mm profiles for CS, 13 CO and 12 CO are taken fromKaźmierczak-Barthel et al (2014) and the sub-mm H 2 O line is taken fromChoi et al (2015). The IR H 2 O line is from our EXES data.…”

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confidence: 99%

Infrared Detection of Abundant CS in the Hot Core AFGL 2591 at High Spectral Resolution with SOFIA/EXES*

Barr

Boogert

DeWitt

et al. 2018

ApJL

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We have performed a 5-8 µm spectral line survey of the hot molecular core associated with the massive protostar AFGL 2591, using the Echelon-Cross-Echelle Spectrograph (EXES) on the Stratospheric Observatory for Infrared Astronomy (SOFIA). We have supplemented these data with a ground based study in the atmospheric M band around 4.5 µm using the iSHELL instrument on the Infrared Telescope Facility Corresponding author: Andrew G. Barr barr@strw.leidenuniv.nl * Observations made at the IRTF and SOFIA (IRTF), and the full N band window from 8-13 µm using the Texas Echelon Cross Echelle Spectrograph (TEXES) on the IRTF.Here we present the first detection of ro-vibrational transitions of CS in this source. The absorption lines are centred on average around -10 kms −1 and the line widths of CS compare well with the hot component of 13 CO (around 10 kms −1 ). Temperatures for CS, hot 13 CO and 12 CO v=1-2 agree well and are around 700 K. We derive a CS abundance of 8×10 −3 and 2×10 −6 with respect to CO and H 2 respectively. This enhanced CS abundance with respect to the surrounding cloud (1×10 −8 ) may reflect sublimation of H 2 S ice followed by gas-phase reactions to form CS.Transitions are in LTE and we derive a density of >10 7 cm −3 , which corresponds to an absorbing region of <0.04 ′′ . EXES observations of CS are likely to probe deeply into the hot core, to the base of the outflow. Submillimeter and infrared observations trace different components of the hot core as revealed by the difference in systemic velocities, line widths and temperatures, as well as the CS abundance.

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The HIFI spectral survey of AFGL 2591 (CHESS)

Cited by 14 publications

References 43 publications

Sofia/Exes Observations of Water Absorption in the Protostar Afgl 2591 at High Spectral Resolution

Sofia/Exes Observations of Water Absorption in the Protostar Afgl 2591 at High Spectral Resolution

Linking low- to high-mass young stellar objects withHerschel-HIFI observations of water

Infrared Detection of Abundant CS in the Hot Core AFGL 2591 at High Spectral Resolution with SOFIA/EXES*

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