arXiv subjects

M. Gerin

Publications and source records attributed to M. Gerin.

At least 55 records · Page 3Linked to original sources

arXiv2016

Planck's Dusty GEMS. II. Extended [CII] emission and absorption in the Garnet at z=3.4 seen with ALMA

We present spatially resolved ALMA [CII] observations of the bright (flux density S=400 mJy at 350 microns), gravitationally lensed, starburst galaxy PLCK G045.1+61.1 at z=3.427, the "Garnet". This source is part of our set of "Planck's Dusty GEMS", discovered with the Planck's all-sky survey. Two emission-line clouds with a relative velocity offset of ~600 km/s extend towards north-east and south-west, respectively, of a small, intensely star-forming clump with a star-formation intensity of 220 Msun/yr/kpc^2, akin to maximal starbursts. [CII] is also seen in absorption, with a redshift of +350 km/s relative to the brightest CO component. [CII] absorption has previously only been found in the Milky Way along sightlines toward bright high-mass star-forming regions, and this is the first detection in another galaxy. Similar to Galactic environments, the [CII] absorption feature is associated with [CI] emission, implying that this is diffuse gas shielded from the UV radiation of the clump, and likely at large distances from the clump. Since absorption can only be seen in front of a continuum source, the gas in this structure can definitely be attributed to gas flowing towards the clump. The absorber could be part of a cosmic filament or merger debris being accreted onto the galaxy. We discuss our results also in light of the on-going debate of the origin of the [CII] deficit in dusty star-forming galaxies.

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arXiv2016

FIR Spectroscopy of the Galactic Center: Hot and Warm Molecular Gas

The angular resolution (~10") achieved by the Herschel Space Observatory ~3.5m telescope at FIR wavelengths allowed us to roughly separate the emission toward the inner parsec of the galaxy (the central cavity) from that of the surrounding circumnuclear disk (the CND). The FIR spectrum toward SgrA* is dominated by intense [Oiii], [Oi], [Cii], [Niii], [Nii], and [Ci] fine-structure lines (in decreasing order of luminosity) arising in gas irradiated by the strong UV field from the central stellar cluster. The high-J CO rotational line intensities observed at the interface between the inner CND and the central cavity are consistent with a hot isothermal component at T~10^{3.1} K and n(H_2)~10^4 cm^{-3}. They are also consistent with a distribution of lower temperatures at higher gas density, with most CO at T~300 K. The hot CO component (either the bulk of the CO column density or just a small fraction depending on the above scenario) likely results from a combination of UV and shock-driven heating. Although this component is beam diluted in our FIR observations, it may be resolved at much higher angular resolution. An ALMA project using different molecular tracers to characterize UV-irradiated shocks in the innermost layers of the CND is ongoing.

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arXiv2016

Spatial distribution of FIR rotationally excited CH+ and OH emission lines in the Orion Bar PDR

The abundance of CH+ and OH and excitation are predicted to be enhanced by the presence of vibrationally excited H2 or hot gas (~500-1000 K) in PDRs with high incident FUV radiation field. The excitation may also originate in dense gas (>10^5 cm-3) followed by nonreactive collisions. Previous observations suggest that the CH+ and OH correlate with dense and warm gas, and formation pumping contributes to CH+ excitation. We examine the spatial distribution of the CH+ and OH emission in the Orion Bar to establish their physical origin and main formation and excitation mechanisms. We present spatially sampled maps of the CH+ J=3-2 transition at 119.8 μm and the OH Λ-doublet at 84 μm in the Orion Bar over an area of 110"x110" with Herschel (PACS). We compare the spatial distribution of these molecules with those of their chemical precursors, C+, O and H2, and tracers of warm and dense gas. We assess the spatial variation of CH+ J=2-1 velocity-resolved line profile observed with Herschel (HIFI). The OH and CH+ lines correlate well with the high-J CO emission and delineate the warm and dense molecular region. While similar, the differences in the CH+ and OH morphologies indicate that CH+ formation and excitation are related to the observed vibrationally excited H2. This indicates that formation pumping contributes to the excitation of CH+. Interestingly, the peak of the rotationally excited OH 84 μm emission coincides with a bright young object, proplyd 244-440, which shows that OH can be an excellent tracer of UV-irradiated dense gas. The spatial distribution of CH+ and OH revealed in our maps is consistent with previous modeling studies. Both formation pumping and nonreactive collisions in a UV-irradiated dense gas are important CH+ J=3-2 excitation processes. The excitation of the OH Λ-doublet at 84 μm is mainly sensitive to the temperature and density.

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arXiv2016

OH+ and H2O+ absorption toward PKS1830-211

We report the detection of OH+ and H2O+ in the z=0.89 absorber toward the lensed quasar PKS1830-211. The abundance ratio of OH+ and H2O+ is used to quantify the molecular hydrogen fraction (fH2) and the cosmic-ray ionization rate of atomic hydrogen (zH) along two lines of sight, located at ~2 kpc and ~4 kpc to either side of the absorber's center. The molecular fraction decreases outwards, from ~0.04 to ~0.02, comparable to values measured in the Milky Way at similar galactocentric radii. For zH, we find values of ~2x10^-14 s^-1 and ~3x10^-15 s^-1, respectively, which are slightly higher than in the Milky Way at comparable galactocentric radii, possibly due to a higher average star formation activity in the z=0.89 absorber. The ALMA observations of OH+, H2O+, and other hydrides toward PKS1830-211 reveal the multi-phase composition of the absorbing gas. Taking the column density ratios along the southwest and northeast lines of sight as a proxy of molecular fraction, we classify the species ArH+, OH+, H2Cl+, H2O+, CH, and HF as tracing gases increasingly more molecular. Incidentally, our data allow us to improve the accuracy of H2O+ rest frequencies and thus refine the spectroscopic parameters.

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arXiv2016

Compression and ablation of the photo-irradiated cloud the Orion Bar

The Orion Bar is the archetypal edge-on molecular cloud surface illuminated by strong ultraviolet radiation from nearby massive stars. Owing to the close distance to Orion (about 1,350 light-year), the effects of stellar feedback on the parental cloud can be studied in detail. Visible-light observations of the Bar(1) show that the transition between the hot ionised gas and the warm neutral atomic gas (the ionisation front) is spatially well separated from the transition from atomic to molecular gas (the dissociation front): about 15 arcseconds or 6,200 astronomical units (one astronomical unit is the Earth-Sun distance). Static equilibrium models(2,3) used to interpret previous far-infrared and radio observations of the neutral gas in the Bar(4,5,6) (typically at 10-20 arcsecond resolution) predict an inhomogeneous cloud structure consisting of dense clumps embedded in a lower density extended gas component. Here we report one-arcsecond-resolution millimetre-wave images that allow us to resolve the molecular cloud surface. In contrast to stationary model predictions(7,8,9), there is no appreciable offset between the peak of the H2 vibrational emission (delineating the H/H2 transition) and the edge of the observed CO and HCO+ emission. This implies that the H/H2 and C+/C/CO transition zones are very close. These observations reveal a fragmented ridge of high-density substructures, photoablative gas flows and instabilities at the molecular cloud surface. The results suggest that the cloud edge has been compressed by a high-pressure wave that currently moves into the molecular cloud. The images demonstrate that dynamical and nonequilibrium effects are important for the cloud evolution.

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arXiv2016

The Far-Infrared Surveyor Mission Study: Paper I, the Genesis

This paper describes the beginning of the Far-Infrared Surveyor mission study for NASA's Astrophysics Decadal 2020. We describe the scope of the study, and the open process approach of the Science and Technology Definition Team. We are currently developing the science cases and provide some preliminary highlights here. We note key areas for technological innovation and improvements necessary to make a Far-Infrared Surveyor mission a reality.

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arXiv2016

The first CO+ image: Probing the HI/H2 layer around the ultracompact HII region Mon R2

The CO+ reactive ion is thought to be a tracer of the boundary between a HII region and the hot molecular gas. In this study, we present the spatial distribution of the CO+ rotational emission toward the Mon R2 star-forming region. The CO+ emission presents a clumpy ring-like morphology, arising from a narrow dense layer around the HII region. We compare the CO+ distribution with other species present in photon-dominated regions (PDR), such as [CII] 158 mm, H2 S(3) rotational line at 9.3 mm, polycyclic aromatic hydrocarbons (PAHs) and HCO+. We find that the CO+ emission is spatially coincident with the PAHs and [CII] emission. This confirms that the CO+ emission arises from a narrow dense layer of the HI/H2 interface. We have determined the CO+ fractional abundance, relative to C+ toward three positions. The abundances range from 0.1 to 1.9x10^(-10) and are in good agreement with previous chemical model, which predicts that the production of CO+ in PDRs only occurs in dense regions with high UV fields. The CO+ linewidth is larger than those found in molecular gas tracers, and their central velocity are blue-shifted with respect to the molecular gas velocity. We interpret this as a hint that the CO+ is probing photo-evaporating clump surfaces.

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arXiv2016

Ionization fraction and the enhanced sulfur chemistry in Barnard 1

Barnard B1b has revealed as one of the most interesting globules from the chemical and dynamical point of view. It presents a rich molecular chemistry characterized by large abundances of deuterated and complex molecules. Furthermore, it hosts an extremely young Class 0 object and one candidate to First Hydrostatic Core (FHSC). Our aim was to determine the cosmic ray ionization rate and the depletion factors in this extremely young star forming region. We carried out a spectral survey towards Barnard 1b as part of the IRAM Large program ASAI using the IRAM 30-m telescope at Pico Veleta (Spain). This provided a very complete inventory of neutral and ionic C-, N- and S- bearing species with, up to our knowledge, the first secure detections of the deuterated ions DCS+ and DOCO+. We used a state-of-the-art pseudo-time-dependent gas-phase chemical model to determine the value of the cosmic ray ionization rate and the depletion factors. The observational data were well fitted with $ζ_{H_2}$ between 3E-17 s$^{-1}$ and 1E-16 s$^{-1}$. Elemental depletions were estimated to be ~10 for C and O, ~1 for N and ~25 for S. Barnard B1b presents similar depletions of C and O than those measured in pre-stellar cores. The depletion of sulfur is higher than that of C and O but not as extreme as in cold cores. In fact, it is similar to the values found in some bipolar outflows, hot cores and photon-dominated regions. Several scenarios are discussed to account for these peculiar abundances. We propose that it is the consequence of the initial conditions (important outflows and enhanced UV fields in the surroundings) and a rapid collapse (~0.1 Myr) that permits to maintain most S- and N-bearing species in gas phase to great optical depths. The interaction of the compact outflow associated with B1b-S with the surrounding material could enhance the abundances of S-bearing molecules, as well.

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arXiv2016

Star Formation and Feedback: A Molecular Outflow-Prestellar Core Interaction in L1689N

We present Herschel, ALMA Compact Array (ACA), and Caltech Submillimeter Observatory (CSO) observations of the prestellar core in L1689N, which has been suggested to be interacting with a molecular outflow driven by the nearby solar type protostar IRAS 16293-2422. This source is characterized by some of the highest deuteration levels seen in the interstellar medium. The change in the NH2D line velocity and width across the core provides clear evidence of an interaction with the outflow, traced by the high-velocity water emission. Quiescent, cold gas, characterized by narrow line widths is seen in the NE part of the core, while broader, more disturbed line profiles are seen in the W/SW part. Strong N2D+ and ND3 emission is detected with the ACA, extending S/SW from the peak of the single-dish NH2D emission. The ACA data also reveal the presence a compact dust continuum source, with a mean size of ~1100 au, a central density of (1-2) 10^7 cm-3, and a mass of 0.2-0.4 Msun. The dust emission peak is displaced ~5" to the south with respect to the N2D+ and ND3 emission, as well as the single-dish dust continuum peak, suggesting that the northern, quiescent part of the core is characterized by spatially extended continuum emission, which is resolved out by the interferometer. We see no clear evidence of fragmentation in this quiescent part of the core, which could lead to a second generation of star formation, although a weak dust continuum source is detected in this region in the ACA data.

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arXiv2015

Ortho-to-para ratio of NH2. Herschel-HIFI observations of ortho- and para-NH2 rotational transitions towards W31C, W49N, W51 and G34.3+0.1

We have used the Herschel-HIFI instrument to observe both nuclear spin symmetries of amidogen (NH2) towards the high-mass star-forming regions W31C (G10.6-0.4), W49N (G43.2-0.1), W51 (G49.5-0.4) and G34.3+0.1. The aim is to investigate the ratio of nuclear spin types, the ortho-to-para ratio (OPR), of NH2. The excited NH2 transitions are used to construct radiative transfer models of the hot cores and surrounding envelopes in order to investigate the excitation and possible emission of the ground state rotational transitions of ortho-NH2 N_(K_a,K_c} J=1_(1,1) 3/2 - 0_(0,0) 1/2 and para-NH2 2_(1,2) 5/2 - 1_(0,1) 3/2$ used in the OPR calculations. Our best estimate of the average OPR in the envelopes lie above the high temperature limit of three for W49N, specifically 3.5 with formal errors of \pm0.1, but for W31C, W51, and G34.3+0.1 we find lower values of 2.5\pm0.1, 2.7\pm0.1, and 2.3\pm0.1, respectively. Such low values are strictly forbidden in thermodynamical equilibrium since the OPR is expected to increase above three at low temperatures. In the translucent interstellar gas towards W31C, where the excitation effects are low, we find similar values between 2.2\pm0.2 and 2.9\pm0.2. In contrast, we find an OPR of 3.4\pm0.1 in the dense and cold filament connected to W51, and also two lower limits of >4.2 and >5.0 in two other translucent gas components towards W31C and W49N. At low temperatures (T \lesssim 50 K) the OPR of H2 is <10^-1, far lower than the terrestrial laboratory normal value of three. In such a "para-enriched H2" gas, our astrochemical models can reproduce the variations of the observed OPR, both below and above the thermodynamical equilibrium value, by considering nuclear-spin gas-phase chemistry. The models suggest that values below three arise in regions with temperatures >20-25 K, depending on time, and values above three at lower temperatures.

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arXiv2015

H2 distribution during 2-phase Molecular Cloud Formation

We performed high-resolution, 3D MHD simulations and we compared to observations of translucent molecular clouds. We show that the observed populations of rotational levels of H2 can arise as a consequence of the multi-phase structure of the ISM.

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arXiv2015

Herschel HIFI Observations of the Sgr A +50 km/s Cloud. Deep Searches for O2 in Emission and Foreground Absorption

To date O2 has definitely been detected in only two sources, namely rho Oph A and Orion, reflecting the extremely low abundance of O2 in the interstellar medium. One of the sources in the HOP program is the +50 km/s Cloud in the Sgr A Complex in the centre of the Milky Way. The Herschel HIFI is used to search for the 487 and 774 GHz emission lines of O2. No O2 emission is detected towards the Sgr A +50 km/s Cloud, but a number of strong emission lines of methanol (CH3OH) and absorption lines of chloronium (H2Cl+) are observed. A 3 sigma upper limit for the fractional abundance ratio of (O2)/(H2) in the Sgr A +50 km/s Cloud is found to be X(O2) less than 5 x 10(-8). However, since we can find no other realistic molecular candidate than O2 itself, we very tentatively suggest that two weak absorption lines at 487.261 and 487.302 GHz may be caused by the 487 GHz line of O2 in two foreground spiral arm clouds. By considering that the absorption may only be apparent, the estimated upper limit to the O2 abundance of less than (10-20) x 10(-6) in these foreground clouds is very high. This abundance limit was determined also using Odin non-detection limits. If the absorption is due to a differential Herschel OFF-ON emission, the O2 fractional abundance may be of the order of (5-10) x 10(-6). With the assumption of pure absorption by foreground clouds, the unreasonably high abundance of (1.4-2.8) x 10(-4) was obtained. The rotation temperatures for CH3OH-A and CH3OH-E lines in the +50 km/s Cloud are found to be 64 and 79 K, respectively, and the fractional abundance of CH3OH is approximately 5 x 10(-7).

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arXiv2015

Spectroscopically resolved far-IR observations of the massive star-forming region G5.89--0.39

The fine-structure line of [OI] at 63micron is an important diagnostic tool in different fields of astrophysics. However, our knowledge of this line relies on observations with low spectral resolution, and the real contribution of each component (PDR, jet) in complex environment of star-forming regions (SFRs) is poorly understood. We investigate the contribution of jet and PDR emission, and of absorption to the [OI]63micron line towards the ultra-compact H{\sc ii} region G5.89--0.39 and study its far-IR line luminosity in different velocity regimes through [OI], [CII], CO, OH, and H2O. We mapped G5.89--0.39 in [OI] and in CO(16--15) with the GREAT receiver onboard SOFIA. We observed the central position of the source in the OH^2Π_{3/2}, J=5/2\toJ=3/2 and ^2Π_{1/2}, J=3/2\toJ=1/2 lines. These data were complemented with APEX CO(6-5) and CO(7-6) and HIFI maps and single-pointing observations in [CII], H2O, and HF. The [OI] spectra in G5.89--0.39 are severely contaminated by absorptions from the envelope and from different clouds along the line of sight. Emission is detected only at HV, clearly associated with the compact north-south outflows traced by extremely HV low-J CO. The mass-loss rate and energetics of derived from [OI] agree well with estimates from CO, suggesting that the molecular outflows in G5.89--0.39 are driven by the jet system seen in [OI]. The far-IR line luminosity of G5.89--0.39 is dominated by [OI] at HV; the second coolant in this velocity regime is CO, while [CII], OH and H2O are minor contributors to the cooling in the outflow. Our study shows the importance of spectroscopically resolved data of [OI]63micron for using this line as diagnostic of SFRs. While this was not possible until now, the GREAT receiver onboard SOFIA has recently opened the possibility of detailed studies of this line to investigate its potential for probing different environments.

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arXiv2015

Velocity-resolved [CII] emission and [CII]/FIR Mapping along Orion with Herschel

We present the first 7.5'x11.5' velocity-resolved map of the [CII]158um line toward the Orion molecular cloud-1 (OMC-1) taken with the Herschel/HIFI instrument. In combination with far-infrared (FIR) photometric images and velocity-resolved maps of the H41alpha hydrogen recombination and CO J=2-1 lines, this data set provides an unprecedented view of the intricate small-scale kinematics of the ionized/PDR/molecular gas interfaces and of the radiative feedback from massive stars. The main contribution to the [CII] luminosity (~85%) is from the extended, FUV-illuminated face of the cloud G_0>500, n_H>5x10^3 cm^-3) and from dense PDRs (G_0~10^4, n_H~10^5 cm^-3) at the interface between OMC-1 and the HII region surrounding the Trapezium cluster. Around 15% of the [CII] emission arises from a different gas component without CO counterpart. The [CII] excitation, PDR gas turbulence, line opacity (from [13CII]) and role of the geometry of the illuminating stars with respect to the cloud are investigated. We construct maps of the [CII]/FIR and FIR/M_Gas ratios and show that [CII]/FIR decreases from the extended cloud component (10^-2-10^-3) to the more opaque star-forming cores (10^-3-10^-4). The lowest values are reminiscent of the "[CII] deficit" seen in local ultra-luminous IR galaxies hosting vigorous star formation. Spatial correlation analysis shows that the decreasing [CII]/FIR ratio correlates better with the column density of dust through the molecular cloud than with FIR/M_Gas. We conclude that the [CII] emitting column relative to the total dust column along each line of sight is responsible for the observed [CII]/FIR variations through the cloud.

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arXiv2015

Probing non polar interstellar molecules through their protonated form: Detection of protonated cyanogen (NCCNH+)

Cyanogen (NCCN) is the simplest member of the series of dicyanopolyynes. It has been hypothesized that this family of molecules can be important constituents of interstellar and circumstellar media, although the lack of a permanent electric dipole moment prevents its detection through radioastronomical techniques. Here we present the first solid evidence of the presence of cyanogen in interstellar clouds through the detection of its protonated form toward the cold dark clouds TMC-1 and L483. Protonated cyanogen (NCCNH+) has been identified through the J=5-4 and J=10-9 rotational transitions using the 40m radiotelescope of Yebes and the IRAM 30m telescope. We derive beam averaged column densities for NCCNH+ of (8.6+/-4.4)e10 cm-2 in TMC-1 and (3.9+/-1.8)e10 cm-2 in L483, which translate to fairly low fractional abundances relative to H2, in the range (1-10)e-12. The chemistry of protonated molecules in dark clouds is discussed, and it is found that, in general terms, the abundance ratio between the protonated and non protonated forms of a molecule increases with increasing proton affinity. Our chemical model predicts an abundance ratio NCCNH+/NCCN of 1e-4, which implies that the abundance of cyanogen in dark clouds could be as high as (1-10)e-8 relative to H2, i.e., comparable to that of other abundant nitriles such as HCN, HNC, and HC3N.

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arXiv2015

Widespread Galactic CF+ absorption: detection toward W49 with the Plateau de Bure Interferometer

To study the usefulness of \CFP\ as a tracer of the regions where C\p\ and \HH\ coexist in the interstellar medium. We used the Plateau de Bure Interferometer to synthesize \CFP\ J=1-0 absorption at 102.6 GHz toward the core of the distant HII region W49N at l = 43.2\degr, b=0.0\degr, and we modeled the fluorine chemistry in diffuse/translucent molecular gas. We detected \CFP\ absorption over a broad range of velocity showing that \CFP\ is widespread in the \HH-bearing Galactic disk gas. Originally detected in dense gas in the Orion Bar and Horsehead PDR, \CFP\ was subsequently detected in absorption from diffuse and translucent clouds seen toward \bll\ and 3C111. Here we showed that \CFP\ is distributed throughout the diffuse and translucent molecular disk gas with N(\CFP)/N(\HH) $= 1.5-2.0\times10^{-10}$, increasing to N(\CFP)/N(\HH) $= 3.5\times10^{-10}$ in one cloud at 39 \kms\ having higher N(\HH) $\approx 3\times10^{21}\pcc$. Models of the fluorine chemistry reproduce the observed column densities and relative abundance of HF, from which \CFP\ forms, but generally overpredict the the column density of \CFP\ by factors of 1.4-4. We show that a free space photodissociation rate $Γ\ga 10^{-9}\ps$, comparable to that of CH, might account for much of the discrepancy but a recent calculation finds a value about ten times smaller. In the heavily blended and kinematically complex spectra seen toward W49, \CFP\ absorption primarily traces the peaks of the \HH\ distribution.

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arXiv2015

A Herschel/HIFI Legacy Survey of HF and H2O in the Galaxy: Probing Diffuse Molecular Cloud Chemistry

We combine Herschel observations of a total of 12 sources to construct the most uniform survey of HF and H2O in our Galactic disk. Both molecules are detected in absorption along all sight lines. The high spectral resolution of the Heterodyne Instrument for the Far-Infrared (HIFI) allows us to compare the HF and H2O distributions in 47 diffuse cloud components sampling the disk. We find that the HF and H2O velocity distributions follow each other almost perfectly and establish that HF and H2O probe the same gas-phase volume. Our observations corroborate theoretical predictions that HF is a sensitive tracer of H2 in diffuse clouds, down to molecular fractions of only a few percent. Using HF to trace H2 in our sample, we find that the N(H2O)-to-N(HF) ratio shows a narrow distribution with a median value of 1.51. Our results further suggest that H2O might be used as a tracer of H2 -within a factor 2.5- in the diffuse interstellar medium. We show that the measured factor of ~2.5 variation around the median is driven by true local variations in the H2O abundance relative to H2 throughout the disk. The latter variability allows us to test our theoretical understanding of the chemistry of oxygen-bearing molecules in the diffuse gas. We show that both gas-phase and grain-surface chemistry are required to reproduce our H2O observations. This survey thus confirms that grain surface reactions can play a significant role in the chemistry occurring in the diffuse interstellar medium n_H < 1000 cm^-3.

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arXiv2015

Nascent bipolar outflows associated with the first hydrostatic core candidates Barnard 1b-N and 1b-S

In the theory of star formation, the first hydrostatic core (FHSC) phase is a critical step in which a condensed object emerges from a prestellar core. This step lasts about one thousand years, a very short time compared with the lifetime of prestellar cores, and therefore is hard to detect unambiguously. We present IRAM Plateau de Bure observations of the Barnard 1b dense molecular core, combining detections of H2CO and CH3OH spectral lines and dust continuum at 2.3" resolution (~ 500 AU). The two compact cores B1b-N and B1b-S are detected in the dust continuum at 2mm, with fluxes that agree with their spectral energy distribution. Molecular outflows associated with both cores are detected. They are inclined relative to the direction of the magnetic field, in agreement with predictions of collapse in turbulent and magnetized gas with a ratio of mass to magnetic flux somewhat higher than the critical value, μ~ 2 - 7. The outflow associated with B1b-S presents sharp spatial structures, with ejection velocities of up to ~ 7 kms from the mean velocity. Its dynamical age is estimated to be ~2000 yrs. The B1b-N outflow is smaller and slower, with a short dynamical age of ~1000 yrs. The B1b-N outflow mass, mass-loss rate, and mechanical luminosity agree well with theoretical predictions of FHSC. These observations confirm the early evolutionary stage of B1b-N and the slightly more evolved stage of B1b-S.

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